Method and apparatus for supporting vehicle to everything service

ABSTRACT

A method for supporting a vehicle communication (connected car or vehicle to everything (V2X)) service in a wireless communication system and an apparatus thereof are provided. The method includes receiving threshold information for reporting a channel busy ratio (CBR), measuring the CBR for a resource pool, identifying whether a reporting condition is satisfied by comparing the measured CBR with the threshold information, and reporting the measured CBR if the reporting condition is satisfied. The present disclosure relates to a communication technique for converging a fifth generation (5G) communication system for supporting higher data rates beyond a fourth generation (4G) system with an Internet of things (IoT) technology, and may be applied to intelligent services based on the 5G communication technology and the IoT-related technology.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 U.S.C. § 119(a) of a Koreanpatent application filed on Nov. 3, 2016 in the Korean IntellectualProperty Office and assigned Serial number 10-2016-0146044, and a Koreanpatent application filed on Nov. 14, 2016 in the Korean IntellectualProperty Office and assigned Serial number 10-2016-0151420, the entiredisclosures of each of which are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a method for supporting a vehiclecommunication (connected car or vehicle to everything (V2X)) service ina wireless communication system.

BACKGROUND

In order to meet the demand for wireless data traffic that is on anincreasing trend after commercialization of fourth generation (4G)communication systems, efforts have been made to develop improved fifthgeneration (5G) or pre-5G communication system. For this reason, the 5Gor pre-5G communication system is also called a beyond 4G networkcommunication system or a post long-term evolution (LIE) system. Inorder to achieve high data rate, implementation of a 5G communicationsystem in an ultrahigh frequency (mmWave) band (e.g., like 60 GHz band)has been considered. In order to mitigate a path loss of radio waves andto increase a transfer distance of the radio waves in the ultrahighfrequency band, technologies of beamforming using array antennas,massive multiple-input multiple-output (MIMO), full dimension MIMO(FD-MIMO), hybrid beamforming, and large-scale antennas for the 5Gcommunication system have been discussed. Further, for system networkimprovement in the 5G communication system, technology developments havebeen made for an evolved small cell, advanced small cell, cloud radioaccess network (cloud RAN), ultra-dense network, device to devicecommunication (D2D), wireless backhaul, moving network, cooperativecommunication, coordinated multi-points (CoMP), and receptioninterference cancellation. In addition, in the 5G system, hybridfrequency shift keying (FSK) and quadrature amplitude modulation (QAM)modulation (FQAM) and sliding window superposition coding (SWSC), whichcorrespond to advanced coding modulation (ACM) systems, and filter bankmulticarrier (FBMC), non-orthogonal multiple access (NOMA), and sparsecode multiple access (SCMA), which correspond to advanced connectiontechnologies, have been developed.

On the other hand, the Internet, which is a human centered connectivitynetwork where humans generate and consume information, is now evolvingto the Internet of things (IoT) where distributed entities, such asthings, exchange and process information. The Internet of everything(IoE), which is a combination of the IoT technology and big dataprocessing technology through connection with a cloud server, hasemerged. As technology elements, such as sensing technology,wired/wireless communication and network infrastructure, serviceinterface technology, and security technology, have been demanded forIoT implementation, a sensor network for machine-to-machine (M2M)connection, M2M communication, machine type communication (MTC), and soforth have been recently researched. Such an IoT environment may provideintelligent Internet technology (IT) services that create a new value tohuman life by collecting and analyzing data generated among connectedthings. The IoT may be applied to a variety of fields including smarthome, smart building, smart city, smart car or connected cars, smartgrid, health care, smart appliances and advanced medical servicesthrough convergence and combination between the existing informationtechnology (IT) and various industries.

Accordingly, various attempts have been made to apply the 5Gcommunication system to IoT networks. For example, technologies ofsensor network, M2M communication, and MTC have been implemented bytechniques for beamforming, MIMO, and array antennas, which correspondto the 5G communication technology. As the big data processingtechnology as described above, application of a cloud RAN would be anexample of convergence between the 5G technology and the IoT technology.

Nowadays, in a wireless communication system, a method for supportingvehicle communication (connected car or vehicle to everything (V2X)) hasbeen sought.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present disclosure.

SUMMARY

Aspects of the present disclosure are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentdisclosure is to provide various operations for supporting vehiclecommunication.

In accordance with an aspect of the present disclosure, a method forsupporting a vehicle to everything (V2X) service by a terminal in awireless communication system includes receiving threshold informationfor reporting a channel busy ratio (CBR), measuring the CBR for aresource pool, identifying whether a reporting condition is satisfied bycomparing the measured CBR with the threshold information, and reportingthe measured CBR if the reporting condition is satisfied.

In accordance with another aspect of the present disclosure, a terminalfor supporting a V2X service in a wireless communication system isprovided. The method includes a transceiver configured to transmit andreceive signals, and at least one processor coupled with thetransceiver, the at least one processor configured to: control thetransceiver to receive threshold information for reporting a CBR,measure the CBR for a resource pool, identify whether a reportingcondition is satisfied by comparing the measured CBR with the thresholdinformation, and control the transceiver to report the measured CBR ifthe reporting condition is satisfied.

According to the various embodiments of the present disclosure,continuity of the vehicle communication service can be secured, andreliability of the vehicle communication service can be heightened.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1A is a diagram illustrating a method for a vehicle terminal totransmit vehicle terminal information to a serving base station (BS)according to a first embodiment of the present disclosure;

FIG. 1B is a diagram illustrating a method for measuring a distanceusing timing alignment information according to a first embodiment ofthe present disclosure;

FIG. 1C is a diagram illustrating a case where a BS calculates adistance through signal measurement information according to a firstembodiment of the present disclosure;

FIG. 1D is a diagram illustrating a case where a terminal transmits areference signal and a serving BS determines a distance according to afirst embodiment of the present disclosure;

FIG. 1E is a diagram illustrating a case where a terminal transmits areference signal as an upward signal and a target BS calculates distanceinformation according to a first embodiment of the present disclosure;

FIG. 1F is a diagram illustrating a method for receiving systeminformation through information exchange between BSs if a service areais changed according to a first embodiment of the present disclosure;

FIG. 1G is a diagram illustrating a method for receiving systeminformation through a handover request if a service area is changedaccording to a first embodiment of the present disclosure;

FIG. 1H is a diagram illustrating a method for receiving systeminformation in a pre-path zone if a service area is changed duringpre-path/handover zone operation according to a first embodiment of thepresent disclosure;

FIG. 1I is a diagram illustrating a method for receiving systeminformation in a handover zone if a service area is changed duringpre-path/handover zone operation according to a first embodiment of thepresent disclosure;

FIG. 1J is a diagram illustrating a method for subdividing andconfiguring a multimedia broadcast/multicast service (MBMS) serviceaccording to a BS zone according to a first embodiment of the presentdisclosure;

FIG. 1K is a diagram illustrating an example of a method for configuringan MBMS service according to a zone according to a first embodiment ofthe present disclosure;

FIG. 2A is a diagram illustrating a vehicle to everything (V2X) packettransmission/reception procedure using a resource pool per zoneaccording to a second embodiment of the present disclosure;

FIG. 2B is a diagram illustrating a channel busy ratio (CBR) statechange of zone 1 according to an embodiment of the present disclosure;

FIG. 2C is a diagram illustrating an example of a BS operation forconfiguring/reconfiguring CBR based zone configuration according to asecond embodiment of the present disclosure;

FIG. 2D is a diagram illustrating another example of a BS operation forconfiguring/reconfiguring CBR based zone configuration according to asecond embodiment of the present disclosure;

FIG. 2E is a diagram illustrating an example of a terminal operation forreporting a zone CBR according to a second embodiment of the presentdisclosure;

FIG. 2F is a diagram illustrating a procedure of changing zone resourcepool configuration based on resource CBR according to a secondembodiment of the present disclosure;

FIG. 2GA is a diagram illustrating zone information example 1 accordingto a second embodiment of the present disclosure;

FIG. 2GB is a diagram illustrating zone information example 2 accordingto a second embodiment of the present disclosure;

FIG. 2H is a diagram illustrating a procedure of changing zone resourcepool configuration based on resource CBR report according to a secondembodiment of the present disclosure;

FIG. 2I is a diagram illustrating a procedure of changing zone resourcepool configuration based on periodic resource CBR report according to asecond embodiment of the present disclosure;

FIG. 2J is a diagram illustrating an example of zone resource pooloperation based on CBR report according to a second embodiment of thepresent disclosure;

FIG. 2K is a diagram illustrating a terminal operation for determiningwhether to perform a channel measurement operation for determiningresource CBR by checking the state of a pedestrian user equipment (UE)according to a second embodiment of the present disclosure;

FIG. 2L is a diagram illustrating a terminal operation method forreporting resource CBR according to a second embodiment of the presentdisclosure;

FIG. 2M is a diagram illustrating a terminal operation for performingresource CBR report using resource configuration information for apacket or a service having high priority according to a secondembodiment of the present disclosure;

FIG. 2N is a diagram illustrating a method for V2X-UE to transmitresource CBR in a connectionless state according to a second embodimentof the present disclosure;

FIG. 2O is a diagram illustrating a method for V2X-UE to transmitresource CBR for inter-public land mobile network (PLMN) resourceaccording to a second embodiment of the present disclosure;

FIG. 2P is a diagram exemplarily illustrating a case where a serving BStransfers to a broadcasting channel information indicating that theserving BS can perform intelligent transportation systems (ITS) bandresource allocation although an ITS frequency band is not providedaccording to a second embodiment of the present disclosure;

FIG. 2Q is a diagram illustrating a case where a serving BS is unable toperform cross-carrier resource allocation according to a secondembodiment of the present disclosure;

FIG. 2R is a diagram illustrating a process in which a neighbor celldoes not transfer information to a serving cell after controllingresources, but a terminal obtains the information by monitoring theneighbor cell directly through a broadcasting channel according to asecond embodiment of the present disclosure;

FIG. 2S is a diagram illustrating a process in which a terminal operatesbased on a predefined resource pool on the assumption that the terminalis out of coverage of a V2X service cell according to a secondembodiment of the present disclosure;

FIG. 2T is a diagram illustrating an example of a terminal operation foroperating a CBR report waiting time in the case of reporting a CBRreport per resource pool according to a second embodiment of the presentdisclosure;

FIG. 2U is a diagram illustrating another example of a terminaloperation for operating a CBR report waiting time in the case ofreporting a CBR report per resource pool according to a secondembodiment of the present disclosure;

FIG. 2V is a diagram illustrating still another example of a terminaloperation for operating a CBR report waiting time in the case ofreporting a CBR report per resource pool according to a secondembodiment of the present disclosure;

FIG. 2W is a block diagram schematically illustrating the configurationof a terminal according to an embodiment of the present disclosure; and

FIG. 2X is a block diagram schematically illustrating the configurationof a BS according to an embodiment of the present disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the present disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thepresent disclosure. In addition, descriptions of well-known functionsand constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of the presentdisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of the presentdisclosure is provided for illustration purpose only and not for thepurpose of limiting the present disclosure as defined by the appendedclaims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

First Embodiment

FIG. 1A is a diagram illustrating a method for a vehicle terminal totransmit vehicle terminal information to a serving BS (BS) according toa first embodiment of the present disclosure.

Referring to FIG. 1A, at operation 101, a terminal 100 may transmitterminal information to a serving BS 110.

The terminal information may include at least one of whether pathinformation configured by the terminal 100 can be used and configuredpath information. For example, if there is the path informationconfigured by a navigation that is one of apps installed in the terminal100, the terminal 100 may transmit to the serving BS 110 an indicatorfor indicating whether the path information can be used as the terminalinformation using the path information. If there is the path informationconfigured by the navigation that is one of the apps installed in theterminal 100, the terminal 100 may transfer the path information to theserving BS 110. The path information may be inscribed, for example, asin Table 1 below.

TABLE 1 locationCoordinates-r10 CHOICE { ellipsoid-Point-r10 OCTETSTRING, ellipsoidPointWithAltitude-r10 OCTET STRING, ...,ellipsoidPointWithUncertaintyCircle-r11 OCTET STRING,ellipsoidPointWithUncertaintyEllipse-r11 OCTET STRING,ellipsoidPointWithAltitudeAndUncertaintyEllipsoid-r11 OCTET STRING,ellipsoidArc-r11 OCTET STRING, Polygon-r11 OCTET STRING } ,horizontalVelocity-r10 OCTET STRING, OPTIONAL, gnss-TOD-msec-r10 OCTETSTRING, OPTIONAL, LocationInfo field descriptions ellipsoidArc ParameterEllipsoidArc defined in 3GPP TS36.355. The first/leftmost bit of thefirst octet contains the most significant bit. ellipsoid-Point ParameterEllipsoid-Point defined in 3GPP TS36.355. The first/leftmost bit of thefirst octet contains the most significant bit.ellipsoidPointWithAltitude Parameter EllipsoidPointWithAltitude definedin 3GPP TS36.355. The first/leftmost bit of the first octet contains themost significant bit. ellipsoidPointWithAltitudeAndUncertaintyEllipsoidParameter EllipsoidPointWithAltitudeAndUncertaintyElllipsoid defined in3GPP TS36.355. The first/leftmost bit of the first octet contains themost significant bit. ellipsoidPointWithUncertaintyCircle ParameterEllipsoid-PointWithUncertaintyCircle defined in 3GP P TS36 .355. Thefirst/leftmost bit of the first octet contains the most significant bit.ellipsoidPointWithUncertaintyEllipse ParameterEllipsoidPointWithUncertaintyEllipse defined in 3GPP TS36.355. Thefirst/leftmost bit of the first octet contains the most significant bit.gnss-TOD-msec Parameter Gnss-TOD-msec defined in 3GPP TS36.355. Thefirst/leftmost bit of the first octet contains the most significant bit.horizontalVelocity Parameter HorizontalVelocity defined in 3GPPTS36.355. The first/leftmost bit of the first octet contains the mostSignificant bit. polygon Parameter Polygon defined in 3GPP TS36.355. Thefirst/leftmost bit of the first octet contains the most significant bit.

If there is the path information configured by the navigation that isone of the apps installed in the terminal 100, the terminal 100 maytransmit an indicator for indicating whether a low-latency operation canbe supported in transmitting the terminal information at operation 101.For example, if there is the path information configured by thenavigation that is one of the apps installed in the terminal 100, theterminal 100 may transmit the indicator in a state where the terminal100 indicates whether the low-latency operation support is possible.

As described above, it is exemplified that the terminal uses anavigation app. However, even in the case where the path information ofthe terminal can be grasped using a radio signal rather than thenavigation app, the terminal 100 can transmit the terminal informationdetermined based on the radio signal at operation 101.

On the other hand, in the case of using a long-term evolution (LTE)system as an embodiment of a method for transmitting the terminalinformation at operation 101, the following operation may be performed.The terminal may transmit user equipment (UE) assistance information,sidelink UE information, or UE capability information to the BS. In thecase where the terminal transmits the UE assistance information, thesidelink UE information, or the UE capability information, at least oneof the path information, an indicator for indicating whether the pathinformation is used, and an indicator for indicating whether alow-latency operation can be supported may be included in theinformation to be transmitted.

As another embodiment using the LTE system, the terminal may transmit UEinformation for using the sidelink to the BS after receiving the systeminformation for the sidelink from the BS. In the case where the terminaltransmits the UE information for using the sidelink, at least one of thepath information, the indicator for indicating whether the pathinformation is used, and the indicator for indicating whether thelow-latency operation can be supported may be included in the UEinformation to be transmitted. The UE information for using the sidelinkand the path information, the indicator for indicating whether the pathinformation is used, or the indicator for indicating whether thelow-latency operation can be supported may be transmitted using the UEassistance information, the sidelink UE information, or the UEcapability information.

If the terminal information is received from the terminal 100, theserving BS 110, at operation 102, may transmit terminal configurationinformation to the terminal 100. For example, in the case of the LTEsystem, the terminal configuration information may be included in radioresource control (RRC) connection reconfiguration.

As an embodiment of the present disclosure, if the path information isusable after the serving BS 110 checks the terminal information atoperation 101, the terminal configuration information may include zoneinformation determined based on the path information transmitted by theterminal 100.

As an example, although not illustrated, the terminal 100 may transmitthe path information generated by navigation through which a departurepoint and destination has been determined to a server that manages thezone through the serving BS 110. Further, the server that manages thezone may be the serving BS 110. The server that manages the zone mayknow in advance information of BSs existing in the movement path of theterminal 100 using the path information sent by the terminal 100. Theserver that manages the zone may generate BS groups through a pre-pathzone and a handover zone through the movement path information of theterminal 100. The pre-path zone is a zone in which bearers can beconnected in advance to BSs that may be target BSs, and the handoverzone is a zone in which the terminal 100 is actually connected to atarget BS. If the pre-path zone and the target zone are determined, theserver that manages the zone may transfer the determined information tothe terminal 100.

The terminal may set a bearer with a target BS in advance using thepre-path zone and the target zone, and may perform a handover to thetarget BS. The serving BS 110 may transfer target BS information of thepre-path zone of the terminal 100 and target BS information of ahandover zone. Further, the serving BS 110 may transfer the target BSinformation of the pre-path zone of the terminal 100. In the lattercase, the target BS of the handover zone may be determined bydetermination conditions of the terminal 100.

The target BS information of the pre-path zone may include resource poolinformation. If the handover zone is determined, the terminal 100 mayperform data transmission/reception in the target BS using the resourcepool information. Further, the target BS information of the pre-pathzone may include the resource pool information to be used for datatransmission/reception until connection configuration to the target BSof the handover zone is completed after the terminal 100 receives ahandover instruction message from the serving BS 110.

Terminal configuration information 102 may include the resource poolinformation to be used by the terminal 100 in a cell of the serving BS110 based on the zone. Further, the terminal configuration information102 may include the resource pool information to be used by the terminal100 while a handover is performed based on the zone. The resource poolinformation to be used while the handover is performed may be used forpacket transmission/reception until the terminal 100 transmits aconnection completion signal to target BSs 120 to 140 after receiving ahandover instruction signal from the serving BS 110.

If the terminal 100 is unable to use path information based on an app ora radio signal, that is, if the terminal 100 does not transmit the pathinformation through terminal information at operation 101 or if theterminal 100 configures “indicator for indicating whether the pathinformation is used=none” or “indicator for indicating whether alow-latency operation can be supported=negative”, the serving BS 110 mayinclude information for causing the terminal 100 to measure the distancein the terminal configuration information to be transmitted.

For example, if network synchronizations between the serving BS 110 andadjacent BSs 120, 130, and 140 coincide with each other, the terminal100 can measure the distance to the target BS using time alignment. Ifthe network synchronizations between the serving BS 110 and the adjacentBSs coincide with each other, the serving BS 110 may include networksynchronization/non-synchronization information in the terminalconfiguration information 102 to be transmitted to the terminal 100.

As another example, if the serving BS 110 supports a positioningfunction, for example, if the serving BS 110 can grasp the location ofthe terminal 100 through a positioning reference signal of an LTEsystem, the serving BS 110 may include information on whether thepositioning reference signal can be used in the terminal configurationinformation to be transmitted to the terminal 100.

Further, the serving BS 110 may include period information for theterminal 100 to transfer the distance information of the terminal to theserving BS 110 in the terminal configuration information to betransmitted by the serving BS 110. Further, the distance information ofthe terminal may include a distance to the target BS measured using thepositioning reference signal.

As an example of the period information, a transmission period valuedetermined in accordance with a speed (e.g., in the case of 60 km/h,terminal distance information is transmitted per 100 msec, whereas inthe case of 120 km/h, the terminal distance information is transmittedper 50 msec) may be included in the terminal configuration information.As another example, the period may be determined based on an event. Forexample, if the terminal distance information measured by the terminal100 is equal to or smaller than a threshold value that is received fromthe serving BS 110, the transmission can start. Further, if the distanceto the serving BS 110 that is measured by the terminal 100 is equal toor smaller than the threshold value and the distance to the target BSs120, 130, and 140 is equal to or larger than the threshold value, thetransmission can start. Further, if the signal of the serving BS 110that is measured by the terminal 100 is smaller than the threshold valuereceived from the serving BS 110, the transmission can start. Further,if the signal of the serving BS 110 that is measured by the terminal 100is lower than the threshold value received from the serving BS 110 andsignals of the target BSs 120, 130, and 140 are higher than thethreshold value, the transmission can start.

If time when the terminal 100 transmits the distance information basedon the event is determined, the terminal 100 may transmit the distanceinformation through a method for once transmitting the distanceinformation when the event occurs or for periodically transmitting thedistance information from the event occurrence time.

In the periodic transmission method or the event based transmissionmethod, the distance information transmission end time may be indicatedby the BS, and if it is equal to or smaller than a threshold valuetransferred from the BS, the transmission of the distance informationmay be ended. As an example, the threshold value may be the minimumdistance between the BS and the terminal.

The terminal 100 may measure relative distances between the target BSs120, 130, and 140 and the terminal 100 using the terminal configurationinformation.

The terminal 100 may determine the distance information transmissiontime through the terminal configuration information transmitted by theserving BS 110. At operation 103, the terminal 100 may transmit thedistance information to the serving BS at a determined time.

For example, the terminal 100 may periodically transfer the distanceinformation at a start time determined by the serving BS 110, or if aspecific event is satisfied (it is determined based on the minimum timeinformation in which the distance information 103 arrives at the servingBS 110), the terminal 100 may periodically transfer the distanceinformation 103. The terminal configuration information 102 may includeat least one of an indicator indicating whether to periodically transferthe distance information, an indicator indicating whether toperiodically transfer the distance information in the case where aspecific event is satisfied, start time information for transferring thedistance information, end time information for transferring the distanceinformation, and an indicator indicating whether to transfer thedistance information in the case where a specific event is satisfied.

The information to be transmitted to the serving BS 110 after theterminal 100 determines to transmit the distance information to theserving BS may include at least one of distance information to the BS,an identifier indicating the BS, and terminal speed.

For example, the distance information may be a relative distance valueto the target BSs 120, 130, and 140 (e.g., 100 m or 120 m), and may be aclass (e.g., near, middle, or far) relatively indicating the distance.

The identifier indicating the target BS 120, 130, or 140 may be a radioidentification (ID) of the BS (e.g., PHYCellID) or a network ID (e.g.,electrocardiographic imaging (ECGI)).

Further, information indicating the speed of the terminal 100 may be anactual speed value (e.g., 60 km/h or 120 km/h) of the terminal, and maybe a class (e.g., low, medium, or high) indicating the speed.

In the case of an LTE system, signaling for the distance informationtransfer of the terminal 100 may include, for example, a measurementreport, sidelink UE information, UE capability information, or UEassistance information.

After the terminal 100 transfers the distance information to the servingBS 110, at operation 104, the serving BS 110 may determine a candidateBS to which the terminal performs a handover based on the distanceinformation and/or a candidate BS for which the terminal shouldpre-configure a bearer to perform data transmission/reception after thehandover.

For example, the serving BS 110 may determine the target BS 120, 130, or140 within the closest distance as the candidate BS through comparisonof the distance information of the target BSs 120, 130, and 140 includedin the distance information at operation 104.

If the speed of the terminal 100 is included in the distance informationtransmitted by the terminal 100, the serving BS 110 may determine thecandidate BS in consideration of the speed of the terminal 100. In anembodiment of FIG. 1A, for example, target 1 120 and target 2 130 may bedetermined as the candidate BSs of the terminal.

After determining the candidate BSs, at operation 105, the serving BS110 may perform bearer pre-configuration with the BSs (target BS_1 120and target BS_2 130) selected as the candidate BSs.

For the bearer pre-configuration, the serving BS 110 may transfer bearerinformation of the terminal 100 that is configured by the serving BS 110to the candidate BSs 120 and 130. The candidate BSs 120 and 130 mayconfigure the bearer based on the bearer information configured by theserving BS, and then may include the bearer information of the candidateBSs 120 and 130 or information (e.g., target BS identifier) of thecandidate BSs 120 and 130 in the bearer to be transferred to the servingBS 110.

The serving BS 110 may exchange the resource pool information, which isto be used while the terminal 100 performs a handover to the candidateBSs 120 and 130, with the candidate BSs 120 and 130.

At operation 106, the serving BS 110 may transfer the information of thecandidate BSs 120 and 130 that is transferred thereto through the bearerpre-configuration task to the terminal 100 as target BS information. Theserving BS 110 may transfer the resource pool information, which is tobe used while the terminal 100 performs the handover, to the terminal100. The resource pool information may be configured per candidate BS120 or 130. The target BS information and the resource pool informationper candidate BS may be included in an RRC connection reconfigurationmessage to be transferred.

The target BS information may include target BS identifiers foridentifying the candidate BSs 120 and 130.

If the handover condition is satisfied, the terminal 100 may perform thehandover through selection of one of the candidate BSs 120 and 130 as anew serving BS. While performing the handover through selection of oneof the candidate BSs 120 and 130 as the new serving BS, the terminal 100may perform data transmission/reception using the received resource poolinformation. As an example, the serving BS 110 may determine theresource pool information to be used by the terminal 100 based on thedistance information of the terminal 100. The resource pool informationmay be included in the RRC connection reconfiguration message to betransferred.

Although the LTE system has been exemplified, the present disclosure canalso be applied even to the next-generation communication system, suchas fifth generation (5G).

Referring to FIGS. 1B to 1E below, various examples for measuring thedistance between the terminal and the target BSs to select the target BSfor the handover will be described.

FIG. 1B is a diagram illustrating a method for measuring a distanceusing timing alignment information according to an embodiment of thepresent disclosure.

Referring to FIG. 1B, synchronization may be performed between theserving BS 110 and the target BSs 120 and 130 through a BSsynchronization procedure at operation 201 according to an embodiment ofthe present disclosure.

For example, in order to perform BS synchronization, the serving BS 110may transmit information of the serving BS 110 (e.g., subframeinformation) to the target BSs 120 and 130, and thus the target BSs 120and 130 may match a subframe boundary with the serving BS 110. Asanother example, in order to perform the BS synchronization, the servingBS and the target BSs 120 and 130 may use GPS/GNSS.

Referring to FIG. 1A, the terminal 100 can know whether distancemeasurement using the timing alignment is possible based on the terminalconfiguration information received from the serving BS 110.

If the terminal 100 determines to measure the distance through thetiming alignment, the terminal 100 may transmit a timing informationrequest to the serving BS 110 at operation 202, and may receive timinginformation from the serving BS 110 at operation 203.

In the case of an LTE system, the timing information request can be madethrough a random access operation. Through a random access preamble sentby the terminal 100, the serving BS 110 can know uplink timing with theterminal 100. After confirming the uplink timing, the serving BS 110 maydetermine the timing alignment based on the uplink timing. Thedetermined timing alignment information may be transmitted from theserving BS 110 to the terminal 100 through a random access response(RAR) message.

At operation 204, the terminal 100 may acquire a downlink propagationdelay time between the serving BS 110 and the terminal 100 throughconfirming of respective reference signals that are transmitted by theserving BS 110 and the target BSs 120 and 130. The terminal 100 may alsoacquire downlink propagation delay time between the target BSs 120 and130 and the terminal 100.

At operation 205, the terminal 100 may acquire the uplink timing for thetarget BSs 120 and 130 and may calculate the distance information usingthe downlink propagation delay time measured between the serving BS 110and the target BSs 120 and 130.

For example, the terminal 100, which has acquired the downlinkpropagation delay time between the serving BS 110 and the target BSs 120and 130, may know how much the timing with the target BSs 120 and 130 istwisted through a difference in downlink propagation delay time betweenthe target BSs 120 and 130 and the serving BS 110.

Through this, the terminal 100 may determine the timing alignment withthe target BSs 120 and 130 by performing correction through comparisonwith the timing alignment acquired from the serving BS 110.

As an example of a correction method, if it is assumed that the timingalignment of the serving BS 110 is TA source, the downlink propagationdelay time of the serving BS 110 is T1, and the downlink propagationdelay time of the target BS 120 is T2, the terminal can acquire thetiming alignment of the target BS 120 through (TA source−2(T1−T2)). Theterminal may calculate the distances to the target BSs 120 and 130 usingthe determined timing alignment information with the target BSs 120 and130. For example, in the case of an LTE system, if the timing alignmentwith the target BS 120 is “1”, it may represent time of 0.5208 ns.

Based on this, the distance between the target BS 120 and the terminal100 may be calculated as about 80 m.

The terminal 100 may report the measurement result of the distance tothe target BSs 120 and 130 measured according to the embodiment of FIG.1B to the serving BS 110. The serving BS 110 may select handovercandidate BSs of the terminal based on the measurement report andperform bearer pre-configuration. According to the embodiment of FIG.1B, the serving BS 110 may select the handover candidate BSs based onthe distance to the target BS distance. As an example, the serving BS110 may select the nearest BS to request the bearer pre-configuration.As another example, the serving BS 110 may select a BS to which thedistance is equal to or smaller than a threshold value to request thebearer pre-configuration. The serving BS 110 may transfer information ofthe selected target BSs 120 and 130 to the terminal 100, and theterminal 100 may perform a handover to one of the target BSs 120 and130.

FIG. 1C is a diagram illustrating a case where a BS calculates adistance through signal measurement information according to anembodiment of the present disclosure.

Referring to FIG. 1C, at operation 301, the serving BS 110 may requestdistance information (measurement) from the terminal 100, and theterminal 100 may measure the distance information to perform ameasurement report operation. Further, the terminal 100 may measure thedistance information in accordance with the terminal configurationinformation received from the BS of FIG. 1A as described above, and mayperiodically transmit the measurement report. Further, the terminal 100may measure the distance information if an event condition is satisfiedin accordance with the terminal configuration information received fromthe BS of FIG. 1A, and may start the measurement report.

At operation 301, a distance information request message may betransmitted from the serving BS 110, or may be transmitted to theterminal 100 through a server. In the case of an LTE system, thedistance information request message may include, for example, a UEinformation request message and an RRC connection reconfigurationmessage.

At operation 302, the terminal 100 may measure reference signals of theserving BS and target BSs based on the distance information requestmessage or the terminal configuration information in FIG. 1A to knowwhether the distance measurement is possible.

The terminal 100 may know a difference in time between the serving BS110 and the target BSs 120 and 130 using the respective referencesignals transmitted from the serving BS 110 and the target BSs 120 and130.

For example, in the case of an LTE system, the reference signals aretransmitted as positioning reference signals, and the terminal mayconfirm a reference signal time difference through the positioningreference signals received from the serving BS 110 and the at least onetarget BS 120 and 130. As another example, in the case of an LTE system,the reference signals are transmitted as sync reference signals, and theterminal may confirm a reference signal time difference through the syncreference signals received from the serving BS 110 and the at least onetarget BS 120 and 130.

At operation 303, the terminal 100 may include the measured referencesignal time difference in signal measurement information to betransmitted to the serving BS 110.

Further, the signal measurement information may be transmitted from theterminal 100 to the server through the serving BS 110. As an example, inthe case of an LTE system, the signal measurement information may beincluded in the measurement report message to be transmitted.

At operation 304, the serving BS 110 may calculate the distances to thetarget BSs 120 and 130 through the reference signal time differenceincluded in the signal measurement information transmitted by theterminal 100.

Further, if the signal measurement information is transmitted to theserver, the server may calculate the distance.

For example, in the case of an LTE system, if the reference signal timedifference is indicated as “1”, it may be expressed as 32 ns, and thusthe distance difference may be calculated as about 10 m.

The serving BS 110 may select target BSs to which the terminal 100 is toperform the handover after calculating the distance difference to thetarget BSs 120 and 130, and may request the bearer pre-configuration.For example, the serving BS 110 may select the nearest BS to request thebearer pre-configuration. As another example, the serving BS 110 mayselect a target BS to which the distance is equal to or smaller than athreshold value to request the bearer pre-configuration from the targetBS. The serving BS 110 may transfer information of the selected targetBSs 120 and 130 to the terminal 100 based on the distance, and theterminal 100 may perform a handover to one of the target BSs 120 and130.

FIG. 1D is a diagram illustrating a case where a terminal transmits areference signal and a serving BS determines a distance according to anembodiment of the present disclosure.

Referring to FIG. 1D, at operation 401, the serving BS 110 may confirmrelative distance information or absolute distance information to thetarget BSs 120 and 130 through BS information exchange at operation 401with the target BSs 120 and 130.

For example, if absolute location coordinates of the target BSs 120 and130 are included in BS information exchange messages that are sent bythe target BSs 120 and 130 to confirm the relative distance between theBSs, the serving BS 110 may calculate the relative distances using theabsolute location coordinates of the serving BS 110 and the target BSs120 and 130.

At operation 402, the terminal 100 may include information whereby theserving BS 110 can calculate the distance information in locationinformation to be transmitted. The location information may include theabsolute coordinates measured by the terminal 100 or messagetransmission time (time stamp) of the terminal 100. For example, thelocation information may include information in Table 1 as above. In thecase of an LTE system, the location information may be transferredusing, for example, an UE assistance information message, a sidelink UEinformation message, an UE capability information message, or ameasurement report message.

Further, the terminal 100 may transmit a pre-configured reference signalas the location information. For example, the terminal 100 may transmitthe reference signals using an upward link based on upward referencesignal configuration included in the terminal configuration information(see FIG. 1A) sent by the serving BS 110. The upward reference signalconfiguration information may include time and frequency information forthe terminal 100 to transmit the upward reference signal, and mayinclude information on whether to transmit the upward reference signalonce or repeatedly in a predetermined section.

At operation 304, if the serving BS 110 receives the locationinformation sent by the terminal 100, it may calculate the distanceinformation between the serving BS 110 and the terminal 100.

After calculating the distance information, the serving BS 110 mayrequest bearer pre-configuration from the target BSs 120 and 130. Aftercalculating the difference in distance to the target BSs 120 and 130,the serving BS 110 may request the bearer pre-configuration throughselection of a target BS to which the terminal 100 is to perform thehandover. For example, the serving BS 110 may select the nearest BS asthe target BS to request the bearer pre-configuration from the targetBS. As another example, the serving BS 110 may select a target BS towhich the distance is equal to or smaller than the threshold value torequest the bearer pre-configuration from the target BS. The serving BS110 may transfer information of the target BSs 120 and 130 selectedbased on the distance to the terminal.

Further, the serving BS 110 and the target BSs 120 and 130 may exchangewith each other resource pool information to be used while the terminalperforms a handover. The serving BS 110 may transfer to the terminal 100the resource pool information to be used when the handover to the targetBSs 120 and 130 is performed. The terminal 100 may perform a handover toone of the target BSs 120 and 130. Further, the serving BS 110 maydetermine the resource pool to be used by the terminal 100 in a cell ofthe serving BS 110 based on the distance information of the terminal 100calculated using the location information.

FIG. 1E is a diagram illustrating a case where a terminal transmits areference signal as an upward signal and a target BS calculates distanceinformation according to an embodiment of the present disclosure.

Referring to FIG. 1E, at operation 501, the serving BS 110 may performBS information exchange with the target BSs 120 and 130. Accordingly,the serving BS information communicating with the terminal 100 may beconfirmed by the target BSs 120 and 130. For example, the target BSs 120and 130 may confirm the serving BS 110 that is currently communicatingwith the terminal through a BS ID of the corresponding.

In this embodiment, the terminal 100 may transmit a pre-configuredreference signal, and the target BSs 120 and 130 may calculate thedistance to the terminal 100 based on the reference signal of theterminal 100. At operation 502, the terminal 100 may transmit thereference signal using an uplink based on upward reference signalconfiguration included in the terminal configuration information (seeFIG. 1A) sent by the serving BS 110. The upward reference signalconfiguration information may include time and frequency informationwhereby the terminal 100 transmits the upward reference signal, and mayinclude information on whether the terminal 100 transmits the upwardreference signal once or repeatedly in a predetermined section.

At operation 304, if the reference signal 402 is received from theterminal 100, the target BSs 120 and 130 may calculate distanceinformation between the target BSs 120 and 130 and the terminal 100.

For example, target BS-1 120 and target BS-2 130 may calculate thedistance information to the terminal 100 through the reference signalreceived from the terminal 100. For example, after measuring thereference signal, the target BS-1 120 may calculate a relative distancebetween the terminal 100 and the target BS-1 120 using a path lossequation (e.g., including transmission power and reception power). Inthe case of the transmission power, the terminal may pre-notify of it.In the case of the transmission power, the serving BS 110 may transferthe value that the terminal has reported to the serving BS 110 to thetarget BS-1 120 and the target BS-2 130. If the distance information iscalculated, the target BSs 120 and 130 may determine whether to performthe bearer pre-configuration as at operation 105.

For example, if the distance calculated by the target BS-1 120 is equalto or smaller than a specific threshold value, the target BS-1 120 mayperform the bearer pre-configuration for the terminal 100 with theserving BS 110 of the terminal 100 acquired through the BS informationexchange.

As another example, the target BS-1 120 and the target BS-2 130 maytransmit the distance information calculated through the referencesignal received from the terminal 100 to the serving BS 110. The servingBS 110 may determine the BS to perform the bearer pre-configuration forthe terminal 100 based on the distance information received from thetarget BS-1 120 and the target BS-2 130. For example, the serving BS 110may select the nearest BS as the target BS to request the bearerpre-configuration from the target BS. Further, the serving BS 110 mayselect the target BS to which the distance is equal to or smaller thanthe threshold value to request the bearer pre-configuration from thetarget BS. The serving BS 110 may transfer the information of the targetBSs 120 and 130 selected based on the distance to the terminal 100.

The serving BS 110 and the target BSs 120 and 130 may exchange with eachother resource pool information to be used while the terminal performs ahandover. The serving BS 110 may transfer to the terminal 100 theresource pool information to be used when the handover to the target BSs120 and 130 is performed. The terminal 100 may perform a handover to oneof the target BSs 120 and 130. Further, the serving BS 110 may determinethe resource pool to be used by the terminal 100 in a cell of theserving BS 110 based on the distance information of the terminal 100calculated using the location information.

FIG. 1F is a diagram illustrating a method for receiving systeminformation through information exchange between BSs if a service areais changed according to an embodiment of the present disclosure.

Referring to FIG. 1F, if the terminal 100 is changed from a serving BS610 in service area 1 to a target BS 620 in service area 2, it mayreceive system information of the target BS 620 through informationexchange between the BSs. The system information of the target BS 620may include an identifier of a service area serviced by the target BS620 (vehicle to everything (V2X) service area identifier), service areafrequency and band information (V2X service area frequency and band),and service resource information (V2X service resource schedulinginformation).

A server 630 may be at least one of a server (e.g., multimediabroadcast/multicast service (MBMS) gateway a broadcast-multicast servicecenter (BM-SC)) that manages multicast/broadcast for V2X, a server(e.g., in the case of an LTE system, a mobile management entity (MME) ora multi-cell/multicast coordination entity (MCE)) that manages a sessionbetween the BSs, and a server that manages a vehicle service andmessage.

The service area is a unit capable of discriminating between themulticast/broadcast services. For example, in the case of an LTE system,the service area may be discriminated through multicast-broadcastsingle-frequency network (MBSFN) capable of performing sync transmissionfor a multi-cell transmission service. Further, the service area mayinclude one or more BSs. In an embodiment of the present disclosure, theservice area may correspond to an area in which the V2Xmulticast/broadcast service is provided through the multicast/broadcastservice method. As another embodiment, the service area may be an area,in which the V2X multicast/broadcast service is provided, discriminatedin the unit of a zone configured by the BS.

Referring to FIG. 1F, the serving BS 610 and the target BS 620 arediscriminated as areas in which different broadcast information (e.g.,different real-time streaming broadcasting channels, different V2Xservice message broadcasts, and different V2X basic security messagebroadcasts) is serviced. For example, the area in which broadcastchannel A is received may be service area 1, and the area in whichbroadcast channel B is received may be service area 2.

The server 630 may configure the service areas in accordance with V2Xbroadcast service channel (e.g., service determined by an upperapplication). The server 630 may manage sessions between the BSsincluded in the service area per service area. Further, the server 630may know the BS located in a boundary area in the service area throughthe location of the BS during configuration of the service areas. Forexample, in an area in which vehicle collision has occurred, serviceareas for providing a V2X basic security message service including avehicle collision message may be configured, and in an area in whichtraffic jam has occurred, a service area for providing a traffic jammessage service may be configured.

Referring to FIG. 1F, at operation 601, the server 630 may provide V2Xservice information (e.g., in the case of an LTE system, temporarymultimedia group identity (TMGI) for V2X or resource information (periodand location) for V2X) to the serving BS 610 and the target BS 620through service area configuration. Further, when the service areaconfiguration information is provided, adjacent BS information of the BS(e.g., BS ID and zone configuration of the BS) may be provided.

At operation 602, if the system information used in the service area ischanged, the serving BS 610 and the target BS 620 may send and receivethe system information between the BSs through information exchange atoperation 602 between the BSs.

As an example of information that may be included as the systeminformation, frequency/band information for receivingmulticast/broadcast information for V2X, channel information forreceiving the multicast/broadcast information for V2X, and resourceinformation (resource location and resource period) for receiving themulticast/broadcast information for V2X may be included. Further, thesystem information may include frequency/band information for receivingmulticast/broadcast information per V2X zone of the BS, channelinformation for receiving the multicast/broadcast information per V2Xzone of the BS, and resource information (resource location and resourceperiod) for receiving the multicast/broadcast information per V2X zoneof the BS.

As an example, a time when the target BS 620 provides information to theserving BS 610 based on an event may be determined. For example, if anevent occurs, in which multicast/broadcast system information for V2X ischanged in the target BS 620, the target BS 620 may transfer the changedmulticast/broadcast system information for V2X of the target BS 620 tothe serving BS 610 using the adjacent BS ID information received fromthe server 630. The event in which the multicast/broadcast systeminformation for V2X is changed in the target BS 620 may include an eventin which the V2X zone configuration information is changed.

As another example, the serving BS 610 may periodically request themulticast/broadcast system information for V2X of the target BS 620 fromthe target BS 620. For example, the serving BS 610 may periodicallyrequest the multicast/broadcast system information for V2X of the targetBS 620 from the target BS 620 through a predetermined period or a periodprovided by the server 630 using the adjacent BS ID information receivedfrom the server 630. If the request for the multicast/broadcast systeminformation for V2X of the target BS is received from the serving BS610, the target BS 620 may transfer the multicast/broadcast systeminformation for V2X of the target BS to the serving BS 610. Further, theserving BS 610 may request the multicast/broadcast system informationincluding V2X zone configuration of the target BS from the target BS620. The target BS 620 may transfer the multicast/broadcast systeminformation including the V2X zone configuration to the serving BS 610.

At operation 603, the terminal 100 may request a handover from theserving BS 610.

If it is determined that the service area of the target BS 620 isdifferent from the service area of the serving BS 610, the serving BS610, at operation 604, may transmit to the terminal 100 a handovercommand message that includes the multicast/broadcast system informationfor V2X of the target BS 620. The handover command 604 message mayinclude the multicast/broadcast system information including the V2Xzone configuration.

As an example, in the case of an LTE system, the terminal 100 maymeasure the signal strength of neighbor BSs, and may transmit ameasurement report to the serving BS 610 as a handover request messagefor determining a handover through the signal strength. If themeasurement report is received from the terminal 100, the serving BS 610may perform handover determination through exchanging of the handoverrequest message with the target BS 620. After the handover isdetermined, the serving BS 610 may transmit a handover command messageto the terminal 100. The serving BS 610 may include themulticast/broadcast system information for V2X of the target BS 620acquired through information exchange between the BSs in the handovercommand message, and may transfer the handover command message to theterminal 100.

As another example, the terminal 100 may provide information fordetermining whether the service area of the target BS 620 is the same asthe service area of the serving BS 610 by including location information(e.g., absolute coordinates or zone ID) of the terminal 100 in themeasurement report message and explicitly transmitting the correspondinglocation to the BS. The serving BS 610 may transmit to the terminal 100the handover command message including information for notifying whetherthe service area of the serving BS 610 is the same as the service areaof the target BS 620. If the service area of the serving BS 610 isdifferent from the service area of the target BS 620, the serving BS 610may transmit the handover command message including the V2X zoneconfiguration information of the target BS 620.

The terminal 100 may acquire broadcast channel information (e.g.,multicast/broadcast resource information for V2X) included inmulticast/broadcast service area system information for V2X of thetarget BS 620 during a handover process through the multicast/broadcastsystem information for V2X of the target BS 620 included in the handovercommand message, and if a handover to the target BS 620 is performed,the terminal 100 may receive multicast/broadcast data for V2X in aservice area of the target BS 620 using the acquired multicast/broadcastresource information for V2X.

As another example, the terminal 100 may acquire whether the servicearea of the serving BS is the same as the service area of the target BSthrough the handover command message, and if the service areas aredifferent from each other, the terminal 100 may acquire the zoneconfiguration information of the target BS. If the handover to thetarget BS 620 is performed, the terminal may receive themulticast/broadcast data based on the acquired zone configurationinformation for V2X.

FIG. 1G is a diagram illustrating a method for receiving systeminformation through a handover request if a service area is changedaccording to an embodiment of the present disclosure.

Referring to FIG. 1G, if the terminal 100 performs a handover from aserving BS 610 in service area 1 to a target BS 620 in service area 2,it may receive multicast/broadcast system information for V2X of thetarget BS 620 through handover request information and handover commandinformation.

A server 630 may be at least one of a server (e.g., multimediabroadcast/multicast service (MBMS) gateway a broadcast-multicast servicecenter (BM-SC)) that manages multicast/broadcast for V2X, a server(e.g., in the case of an LTE system, a mobile management entity (MME) ora multi-cell/multicast coordination entity (MCE)) that manages a sessionbetween the BSs, and a server that manages a vehicle service andmessage.

The service area is a unit capable of discriminating between themulticast/broadcast services for V2X. For example, in the case of an LTEsystem, the service area may be discriminated through MBSFN capable ofperforming sync transmission for a multi-cell transmission service.Further, the service area may include one or more BSs. The service areamay correspond to an area in which the V2X multicast/broadcast serviceis provided through the multicast/broadcast service method. Further, theservice area may be discriminated in the unit of a zone configured bythe BS, and may be subdivided into V2X multicast/broadcast services perzone or partial zone.

Referring to FIG. 1G, the serving BS 610 and the target BS 620 arediscriminated as areas in which different broadcast information (e.g.,different real-time streaming broadcasting channels, different V2Xservice message broadcasts, and different V2X basic security messagebroadcasts) is serviced. For example, the area in which broadcastchannel A is received may be service area 1, and the area in whichbroadcast channel B is received may be service area 2.

The server 630 may configure the service areas in accordance with V2Xbroadcast service channel (e.g., service determined by an upperapplication). The server 630 may manage sessions between the BSsincluded in the service area per service area. Further, the server 630may know the BS located in a boundary area in the service area throughthe location of the BS during configuration of the service areas. Forexample, in an area in which vehicle collision has occurred, serviceareas for providing a V2X basic security message service including avehicle collision message may be configured, and in an area in whichtraffic jam has occurred, a service area for providing a traffic jammessage service may be configured.

Referring to FIG. 1G, at operation 701, the server 630 may provide V2Xservice information (e.g., in the case of an LTE system, temporarymultimedia group identity (TMGI) for V2X or resource information (periodand location) for V2X) to the serving BS 610 and the target BS 620through service area configuration. Further, when the service areaconfiguration information is provided, adjacent BS information of the BS(e.g., base station ID) may be provided.

At operation 702, the terminal 100 may request a handover from theserving BS 610, and at operation 703, the serving BS 610 may transfer ahandover request message to the target BS 620. The handover requestmessage may include frequency/band information for receivingmulticast/broadcast information for V2X of the target BS 620 orinformation for requesting system information for V2X.

As an example, in the case of an LTE system, the terminal 100 measuresthe signal strength of neighbor BSs, and may transmit a measurementreport to the serving BS 610 as a handover request message. If themeasurement report is received from the terminal 100, the serving BS 610may determine BS change, and then transmit the handover request messageto the target BS 620. The handover request message includes bearerinformation of the serving BS 610, or system information request for themulticast/broadcast service for V2X for receiving themulticast/broadcast service for V2X after movement to the target BS 620.

Further, the terminal 100 may provide information for determiningwhether the service area of the target BS 620 is the same as the servicearea of the serving BS 610 by including location information (e.g.,absolute coordinates or zone ID) of the terminal 100 in the measurementreport message and explicitly transmitting the corresponding location tothe BS. If the service area of the target BS 620 is different from theservice area of the serving BS 610, the serving BS 610 may pre-transmitservice information (e.g., zone configuration and multicast/broadcastresource information) in the target BS 620 to the terminal.

At operation 704, if the handover request message is received, thetarget BS 620 transmits a handover request response message to theserving BS 610.

As an example, if the target BS 620 receives the handover requestmessage including a request for the multicast/broadcast systeminformation for V2X from the serving BS 610, the target BS 620 mayinclude the multicast/broadcast system information for V2X of the targetBS 620 in the handover request response message to be transmitted.

As an example of information that may be included as the systeminformation, channel information for receiving multicast/broadcastinformation for V2X or multicast/broadcast resource information(resource location and resource period) for V2X may be included.

If the handover request response message is received, the serving BS610, at operation 705, may transmit the handover command message to theterminal 100. The serving BS 610 may include the handover request andthe multicast/broadcast service system information for V2X of the targetBS 620 acquired through the handover request response in the handovercommand message to be transferred to the terminal 100.

The terminal 100 may acquire multicast/broadcast channel information(e.g., resource information) included in service area system informationof the target BS 620 during a handover process through themulticast/broadcast service system information for V2X of the target BS620 included in the handover command message, and if a handover to thetarget BS 620 is performed, the terminal 100 may receivemulticast/broadcast data for V2X in a service area of the target BS 620using the acquired multicast/broadcast resource information for V2X.

FIG. 1H is a diagram illustrating a method for receiving systeminformation in a pre-path zone if a service area is changed duringpre-path/handover zone operation according to an embodiment of thepresent disclosure.

Referring to FIG. 1H, if the terminal 100 is changed from a serving BS810 in service area 1 to a target BS 820 in service area 2, it mayreceive multicast/broadcast system information for V2X of the target BS820 through a pre-path request.

A server 830 may be at least one of a server (e.g., multimediabroadcast/multicast service (MBMS) gateway a broadcast-multicast servicecenter (BM-SC)) that manages multicast/broadcast for V2X, a server(e.g., in the case of an LTE system, a mobile management entity (MME) ora multi-cell/multicast coordination entity (MCE)) that manages a sessionbetween the base stations (BSs), and a server that manages a vehicleservice and message.

The service area is a BS unit capable of pre-configuring a bearer or aunit capable of discriminating between V2X multicast/broadcast services.For example, in the case of an LTE system, the service area may bediscriminated through MBSFN capable of performing sync transmission fora multi-cell transmission service. Further, the service area may includeone or more BSs. The service area may correspond to an area in which theV2X multicast/broadcast service is provided through themulticast/broadcast service method.

As an example, the service area may be determined through UE informationtransmitted by the terminal 100 at operation 801. The UE information mayinclude a movement path of the terminal 100 configured by a navigation,and may include relative distance information to the BS determined bythe terminal 100. Further, the UE information may include V2X serviceinformation to which the terminal 100 has subscribed.

Referring to FIG. 1H, the serving BS 810 and the target BS 820 arediscriminated as areas in which different broadcast information (e.g.,different real-time streaming broadcasting channels, different V2Xservice message broadcasts, and different V2X basic security messagebroadcasts) is serviced. Further, the corresponding service area may becomposed of a pre-path zone. For example, the area in which broadcastchannel A is received may be service area 1 as well as pre-path zone 1,and the area in which broadcast channel B is received may be servicearea 2 as well as pre-path zone 2. Further, the area in which broadcastchannel A is received may be service area 1 as well as pre-path zone 1,and the area in which broadcast channel B is received may be servicearea 2 as well as pre-path zone 1.

The server 830 may configure the service areas in accordance withmulticast/broadcast service channel for V2X (e.g., service determined byan upper application). The server 830 may manage sessions between theBSs included in the service area per multicast/broadcast service areafor V2X. Further, the server 830 may know the BS located in a boundaryarea in the service area through the location of the BS duringconfiguration of the service areas.

At operation 802, the server 830 may provide V2X service information(e.g., in the case of an LTE system, temporary multimedia group identity(TMGI) for V2X, resource information (period and location) for V2X), orlocation information (ex, zone ID, and zone configuration) to theserving BS 810 and the target BS 820 through transmission ofpre-path/handover zone information. Further, when the pre-path/handoverzone information is transmitted, adjacent BS information (e.g., BS ID)of the BS may be provided.

At operation 803, the terminal 100 transmits a pre-path request messageto the serving BS 810 during entering into the pre-path zone. Atoperation 804, the serving BS 810 transmits a target BS informationrequest to the target BS 820 after receiving the pre-path requestmessage from the terminal 100.

A method for the serving BS 810 to determine the target BS that willtransmit the pre-path request is as follows. The serving BS 810 may knowwhat BS is a BS that is located in a boundary portion of the servicearea (e.g., pre-path/handover zone boundary) through transmission of thepre-path/handover zone information. For example, in the case ofconfiguring the pre-path zone based on a BS absolute location, theserver 830 may transfer the pre-path zone information to the serving BS810 and the target BS 820. Based on the pre-path zone information, theBSs 810 and 820 may determine whether they are BSs located in a boundaryportion of the service area. Further, the pre-path/handover zoneinformation may include BS IDs. The serving BS 810 may transmit a BSinformation request message to the target BS 820 using the BS ID locatedin the service area boundary area. The BS information request messagemay include information for requesting the multicast/broadcast servicesystem information for V2X of the target BS 820.

If the BS information request message is received, the target BS 820, atoperation 805, transmits a BS information transfer message to theserving BS 810.

For example, if the BS information request message is received from theserving BS 610, the target BS 620 includes the multicast/broadcastservice system information for V2X of the target BS 820 in the BSinformation transfer message to be transmitted.

The multicast/broadcast service system information for V2X may include,for example, channel information for receiving the multicast/broadcastservice information for V2X or multicast/broadcast service resourceinformation (resource location or resource period) for V2X.

If the BS information transfer message is received, the serving BS 810,at operation 806, may transmit a pre-path response message to theterminal 100. The pre-path response message may include themulticast/broadcast service system information for V2X of the target BS820 acquired through BS information request and BS information transfermessages, and may be transferred to the terminal 100.

The terminal 100 may be configured to use multicast/broadcast servicechannel information (e.g., resource information) for V2X included in theservice area system information of the target BS 820 during a handoverprocess through the multicast/broadcast service system information forV2X of the target BS 820 included in the pre-path response message.

FIG. 1I is a diagram illustrating a method for receiving systeminformation in a handover zone if a service area is changed duringpre-path/handover zone operation according to an embodiment of thepresent disclosure.

Referring to FIG. 1I, if the terminal 100 performs a handover from aserving BS 810 in service area 1 to a target BS 820 in service area 2,it may receive information (e.g., C-radio network temporary identifier(C-RNTI) of the target BS or preamble information of the target BS) thatcan be used for the handover to the target BS 820 through transmissionof pre-path/handover zone information at operation 802.

A server 830 may be at least one of a server (e.g., multimediabroadcast/multicast service (MBMS) gateway a broadcast-multicast servicecenter (BM-SC)) that manages multicast/broadcast for V2X, a server(e.g., in the case of an LTE system, a mobile management entity (MME) ora multi-cell/multicast coordination entity (MCE)) that manages a sessionbetween the BSs, and a server that manages a vehicle service andmessage.

The service area is a BS unit capable of pre-configuring a bearer or aunit capable of discriminating between V2X multicast/broadcast services.For example, in the case of an LTE system, the service area may bediscriminated through MBSFN capable of performing sync transmission fora multi-cell transmission service. Further, the service area may includeone or more BSs. The service area may correspond to an area in which theV2X multicast/broadcast service is provided through themulticast/broadcast service method. Further, the service area may bediscriminated in the unit of a zone configured by the BS, and may besubdivided to provide different V2X multicast/broadcast services perzone or partial zone.

As an example, the service area may be determined through UE informationtransmitted by the terminal 100 at operation 801. The UE information mayinclude a movement path of the terminal 100 configured by a navigation,and may include relative distance information to the BS determined bythe terminal 100.

Referring to FIG. 1I, the serving BS 810 and the target BS 820 arediscriminated as areas in which different broadcast information (e.g.,different real-time streaming broadcasting channels, different V2Xservice message broadcasts, and different V2X basic security messagebroadcasts) is serviced. Further, the corresponding service area may becomposed of a pre-path zone. For example, the area in which broadcastchannel A is received may be service area 1 as well as pre-path zone 1,and the area in which broadcast channel B is received may be servicearea 2 as well as pre-path zone 2. Further, the area in which broadcastchannel A is received may be service area 1 as well as pre-path zone 1,and the area in which broadcast channel B is received may be servicearea 2 as well as pre-path zone 1.

The server 830 may configure the service areas in accordance withmulticast/broadcast service channel for V2X (e.g., service determined byan upper application). The server 830 may manage sessions between theBSs included in the service area per multicast/broadcast service areafor V2X. Further, the server 830 may know the BS located in a boundaryarea in the service area through the location of the BS duringconfiguration of the service areas.

At operation 802, the terminal 100 may acquire pre-path/handover zoneinformation from the server 830. At operation 901, during entering of ahandover zone, the terminal 100 may transmit an uplink resource requestmessage to the target BS 820 using information of the target BS (e.g.,preamble of the target BS) obtained from the pre-path/handover zoneinformation. After receiving the uplink resource request message, thetarget BS 820, at operation 902, may transmit uplink resource allocationinformation to the terminal 100.

As an example, in an LTE system, the terminal 100 may transmit theuplink resource request information through transmission of a randomaccess preamble message. For example, in the case of using the preambleallocated through a system information transmission request for V2Xamong random access preambles, the target BS 820 may determine whetherto transfer system information for V2X to the terminal 100. The targetBS 820 may provide random access response information in response to therandom access preamble. The target BS 820 may include the systeminformation for V2X of the target BS 820 in the random access responseinformation to be transferred to the terminal 100.

As an example of V2X information that can be included as the systeminformation, channel information for receiving multicast/broadcastinformation for V2X or resource information (resource location orresource period) may be included.

The terminal 100 may be configured to receive a multicast/broadcastservice for V2X of the target BS 820 through the system information forV2X of the target BS 820 included in the uplink resource allocationmessage.

FIG. 1J is a diagram illustrating a method for subdividing andconfiguring an MBMS service according to a BS zone according to anembodiment of the present disclosure.

Referring to FIG. 1J, at operation 1001, a serving BS 1010 may transmitBS information to a server 1020. Based on the BS information, the server1020 may provide a multicast/broadcast service for V2X in detail to theserving BS 1010. At operation 1002, the terminal 100 may transmit UEinformation to the server 1020.

The server 1020 may be at least one of a server (e.g., multimediabroadcast/multicast service (MBMS) gateway a broadcast-multicast servicecenter (BM-SC)) that manages multicast/broadcast for V2X, a server(e.g., in the case of an LTE system, a mobile management entity (MME) ora multi-cell/multicast coordination entity (MCE)) that manages a sessionbetween the BSs, and a server that manages a vehicle service andmessage.

The service area is a BS unit capable of pre-configuring a bearer or aunit capable of discriminating between V2X multicast/broadcast services.For example, in the case of an LTE system, the service area may bediscriminated through MBSFN capable of performing sync transmission fora multi-cell transmission service. Further, the service area may includeone or more BSs. The service area may correspond to an area in which theV2X multicast/broadcast service is provided through themulticast/broadcast service method. Further, the service area may besubdivided into V2X multicast/broadcast services that are discriminatedin the unit of a zone configured by the BS.

An embodiment of a method for configuring a service area is as follows.In order to support a multicast/broadcast service for V2X, the servingBS 1010 may transmit the BS information to the server 1020. The BSinformation may include a BS ID that has sent the BS information, a zoneID used by the BS, or a method for determining the zone ID (e.g.,equation based on a zone width, a zone height, and the number of zones).

Further, the service area may be determined based on UE informationtransmitted by the terminal 100. The UE information may include amessage for V2X generated by the terminal 100 or subscribed V2X serviceinformation. The message for V2X generated by the terminal 100 may bediscriminated by at least one of a per packet priority value, a logicalchannel ID, a logical channel group ID, or a V2X service type.

The server 1020 may configure a service area using at least one of theUE information and the BS information. As an example, in the case of anLTE system, the server 1020 may be an MBMS coordination entity (MCE).The server 1020 may determine whether a vehicle safety service is usedthrough the V2X service information included in the UE information.Further, the server 1020 may know area information (ex or zone ID) beingused by the BS through the BS information. The server 1020 may configurean MBMS service area to the BS through the UE information or the BSinformation. For example, subframe period and information may bedifferently allocated in accordance with different multicast/broadcastservices for V2X of the respective BS zones.

At operation 1003, the server 1020 may transfer information configuredas different multicast/broadcast services for V2X in accordance with thezone to the serving BS 1010. The multicast/broadcast configurationinformation may include resource information (ex, subframe location andperiod) allocated in accordance with the zone, a service ID, or bearerinformation.

If information configured as a multicast/broadcast service for V2X perzone is received, the serving BS 1010, at operation 1004, transmitsconfiguration information to the terminal 100 so that the terminal 100can configure the multicast/broadcast service for V2X. In the case of anLTE system, the multicast/broadcast configuration message for theterminal 100 may be transmitted as the system information or may betransferred as an RRC message. Further, as the multicast/broadcastconfiguration information, resource information (ex, subframe locationand period) allocated in accordance with the zone or a service ID may beincluded.

FIG. 1K is a diagram illustrating an example of a method for configuringa multimedia broadcast multicast service (MBMS) in accordance with azone.

A BS may allocate resources or provide multicast/broadcast services forV2X through discrimination of zones. For example, a BS (eNB1) may dividean area into zone 1 to zone 9, and a BS (eNB2) may divide an area intozone 1 to zone 9. The zone may be changed in accordance with situations(e.g., terminal CBR situations), and respective BSs may operatedifferent zone configurations. In the area divided into zones in the BS,multicast/broadcast services for V2X are discriminated per zone througha server (e.g., server for MBMS service configuration). For example, themulticast/broadcast service for V2X in zone 1 of the BS (eNB1) maydiffer from the multicast/broadcast service for V2X in zone 1 of the BS(eNB2). Further, multicast/broadcast resources for V2X of zones used inthe BS may differ from each other. For example, resource location andperiod used in zone 1 of the BS (eNB1) may differ from resource locationand period used in zone 2 of the BS (eNB1).

For example, if it is necessary to transmit a collision notificationmessage among vehicle safety messages in zone 3 of the BS (eNB1) toanother zone (e.g., related road), the server may configure zone 2, zone3, zone 5, and zone 6 of the BS (eNB1) as the same service area.Further, the server may configure zone 1 and zone 4 of the adjacent BS(eNB2) as the same service area. The resource location and period usedin zone 3 of the BS (eNB1) may differ from the resource location andperiod used in zone 1 of the BS (eNB2).

Further, for service continuity of the notification message in the casewhere the terminal moves from zone 1 of the BS (eNB2) to one of zone 2,zone 3, zone 5, and zone 6 of the BS (eNB1), it is necessary for theterminal to pre-receive zone configuration and resource information ofthe BS (eNB1). The BS (eNB2) may pre-transfer to the terminal zoneconfiguration of the BS (eNB1) and multicast/broadcast resourceinformation for V2X.

Second Embodiment

The second embodiment of the present disclosure relates to a method foroperating a V2X service resource pool based on the location of a V2Xterminal in order to heighten reliability of a vehicle communication(connected car or vehicle to everything (V2X)) service in a wirelesscommunication system. The V2X terminal may include a vehicle terminal, apedestrian terminal supporting a V2X service, or a road side unit (RSU)terminal supporting the V2X service.

FIG. 2A is a diagram illustrating a V2X packet transmission/receptionprocedure using a resource pool per zone according to an embodiment ofthe present disclosure.

Referring to FIG. 2A, at operation 1101, a BS 1110 may transmit zoneconfiguration information to terminals 1120 and 1130. The zoneconfiguration information may include information that is necessary toacquire resource pool information allocated per zone. For example, thezone configuration information may include at least one of a width of azone basic unit for deriving a zone ID, a length of the zone basic unit,and a resource pool per zone ID. As an example, in an LTE system, thezone configuration information may be transmitted through a systeminformation block (SIB) message. As another example, in an LTE system,the zone configuration information may be pre-configured in theterminal. As still another example, in an LTE system, the zoneconfiguration information may be transmitted through an RRC connectionreconfiguration message.

At operations 1102 and 1103, terminal 1 1120 and terminal 2 1130 maydetermine a zone ID based on the zone configuration information andtheir own locations. At operations 1104 and 1105, terminal 1 1120 andterminal 2 1130 may determine resource pool information corresponding tothe zone ID based on the zone configuration information. At operations1106 and 1107, terminal 1 1120 and terminal 2 1130 may transmit packetsin the acquired resource pool.

FIG. 2B is a diagram illustrating a channel busy ratio (CBR) statechange of zone 1 according to an embodiment of the present disclosure.

Referring to FIG. 2B, a resource to be used by the UE located in zone 1may be determined in accordance with the zone configuration information.If zone 1 is not congested as shown on the left side of FIG. 2B, UEslocated in zone 1 may easily acquire transmission resources in aresource pool allocated to zone 1. In contrast, if many UEs are locatedin zone 1 as shown on the right side of FIG. 2B to cause a CBRsituation, contention probability is heightened in the case where UEslocated in zone 1 acquire transmission resources in the resource poolallocated to zone 1, and delay may occur in acquiring the resources. Ifa case corresponding to the right side of FIG. 2B occurs, it isnecessary for the BS to perform a resource pool reallocation or resourcepool reconfiguration procedure for lowering the CBR situation of zone 1.The BS may receive a report of the busy situation of the zone from theUE using the zone based resource pool so as to perform the resource poolreallocation or resource pool reconfiguration procedure.

In an embodiment of the present disclosure, in the case where the BSconfigures a zone based resource pool reflecting the resource CBR, amethod by the BS for determining the resource CBR is as follows.

In the case where the BS allocates a resource to the terminal, the BSmay determine the resource CBR of each zone based on resource allocationrequest information of the terminal located in each zone. Informationused by the BS to determine the resource CBR of each zone may include atleast one of a zone ID of the terminal, terminal location (locationinfo), packet information (e.g., logical channel group, logical channelpriority, and priority per packet) that the terminal intends to transmitusing the resource, resource use amount requested by the terminal, andresource use period requested by the terminal. Based on the resourceallocation request information of each terminal, the BS may calculatenecessary resources per zone or per packet priority of each zone, andmay determine the CBR of the resource allocated to the resource pool ofeach zone.

As an example, if the ratio of the resource request amount for each zoneto the resource allocation amount for each zone is equal to or higherthan threshold value A, it may be determined that the zone is busy. Inthis case, the BS may reconfigure the zone configuration in a directionto lower the zone CBR. Further, if the ratio of the resource requestamount for each zone to the resource allocation amount for each zone islower than threshold value B, it may be determined that the zone is notbusy. In this case, the BS may reconfigure the zone configuration in adirection to maximally use the zone resource. In the case where theresource CBR of each zone maintains a value between threshold value Band threshold value A, it may be determined that the zone configurationis proper. As another example, the BS may reconfigure the zoneconfiguration through operating of the CBR threshold value X only. TheCBR corresponds to the ratio of the resource request amount for eachzone to the resource allocation amount for each zone. If the CBR of eachzone is higher than the threshold value X, the BS may determine that theresource of the zone is busy, whereas if the CBR of each zone is equalto or lower than the threshold value X, the BS may determine that theresource of the zone is not busy. The BS, which has calculated the zoneCBR based on the CBR threshold value X, may determine whether toreconfigure the zone configuration, and may transmit the reconfiguredzone configuration or the existing zone configuration.

In an embodiment of the present disclosure, in the case where theterminal itself selects the resource from the determined resource pool,the BS may determine the resource CBR of the zone through reception ofthe CBR information report from the terminal. The report of the CBR ofthe terminal may be performed in the case where the CBR threshold valuedetermined by the BS is satisfied or in the case where the request forthe CBR report is received from the BS. The CBR threshold valuedetermined by the BS may be inscribed as threshold value A, thresholdvalue B, or threshold value X. The threshold value A may be determinedby the BS or the system based on the CBR value whereby it is determinedthat the zone monitored by the terminal is busy, and the threshold valueB may be determined based on the CBR value whereby it is determined thatthe zone monitored by the terminal is not busy. The threshold value Aand the threshold value B may be included in the zone configuration thatis transmitted by the BS. The threshold value X may be determined by theBS or the system based on the CBR value whereby it is determined thatthe zone monitored by the terminal is busy. The threshold value X may beincluded in the zone configuration that is transmitted by the BS. TheCBR value measured by the terminal may be measured by sensing theresource pool of the zone in which the terminal is located. As anexample, the terminal may determine the resource CBR value by measuringthe received signal strength indication (RSSI) of the packet DMRStransmitted using the resource pool. As another example, the terminalmay determine the resource CBR value by measuring the energy level forthe resource pool.

In various embodiments of the present disclosure, the operation ofcomparing the CBR value with the CBR threshold value may include both acase where the CBR threshold boundary value is included for comparisonand a case where the CBR threshold boundary value is excluded forcomparison.

As an example, if the zone CBR value of the terminal is larger than thethreshold value A, the terminal may report to the BS at least one of azone ID monitored by the terminal itself, terminal location (locationinfo), indication information for indicating that the zone is busy, anda CBR value of the zone.

As another example, if the CBR report of the zone being used by theterminal is requested by the BS, the terminal may report to the BS atleast one of the zone ID monitored by the terminal itself, terminallocation (location info), indication information for indicating that thezone is busy, indication information for indicating that the zone is notbusy, and CBR value of the zone. In this case, the terminal maydetermine whether the zone is busy based on the CBR threshold values Aand B, and the threshold value X provided by the BS.

Based on the CBR situation of the zone reported by the terminal, the BSmay determine to reconfigure the zone configuration, and configures anew zone configuration to be transmitted. If it is determined that theBS does not reconfigure the zone configuration, the BS may transmit theexisting zone configuration.

In an embodiment of the present disclosure, an operation for the BS todetermine whether to reconfigure the zone configuration using the zoneCBR reported by the terminal is as follows.

The BS may receive from the terminal zone information and a resource CBRvalue for the zone. The BS may calculate the resource CBR value for thezone by gathering resource CBR values received from several terminalsthat belong to the zone. As an example, the BS may calculate an averageof the resource CBR values collected for a time when the resource CBRreports are gathered. If the calculated resource CBR value is equal toor larger than threshold value A, the BS may determine that the zone isbusy. If the calculated resource CBR value is equal to or smaller thanthreshold value B, the BS may determine that the zone is not busy. Ifthe calculated resource CBR value is a value between threshold value Aand threshold value B, the BS may determine that the CBR of the zone isproper. Through the above-described method, the BS may calculate theresource CBR values for all zones in the cell. Based on the resource CBRvalues calculated for all the zones, the BS may reconfigure the zoneconfiguration in a manner that the resource is reduced with respect tothe non-busy zone, and the resource is increased with respect to thebusy zone.

According to another embodiment, even in the case where the terminalreports a resource busy indicator or a resource non-busy indicatorrather than the resource CBR value for the zone, the BS may determinethe resource CBR based on the resource busy indicator or the resourcenon-busy indicator. As an example, the BS may calculate an average ofthe number of resource busy indicators collected for a time when theresource CBR reports are gathered. The BS may calculate an average ofthe number of resource non-busy indicators collected for a time when theresource CBR reports are gathered. If the calculated resource CBR valueis equal to or larger than threshold value A, the BS may determine thatthe zone is busy. If the calculated resource CBR value is equal to orsmaller than threshold value B, the BS may determine that the zone isnot busy. If the calculated resource CBR value is a value betweenthreshold value A and threshold value B, the BS may determine that theCBR of the zone is proper. Through the above-described method, the BSmay calculate the resource CBR values for all zones in the cell. Basedon the resource CBR values calculated for all the zones, the BS mayreconfigure the zone configuration in a manner that the resource isreduced with respect to the non-busy zone, and the resource is increasedwith respect to the busy zone.

In an embodiment of the present disclosure, if a mode in which the BSallocates a resource to the terminal and a mode in which the terminalitself selects a resource coexist, the BS may measure the resource CBRof the zone in consideration of both the resource CBR determined basedon the resource allocation request information of the terminal and theresource CBR reported by the terminal. Further, based on the measuredzone resource CBR, the BS may reconfigure or maintain the zoneconfiguration based on the measured zone resource CBR. The operation forthe BS to determine the reconfiguration of the zone configuration basedon the resource allocation request of the terminal and the resource CBRreport of the terminal is as follows.

The BS may calculate the resource CBR values for the respective zonesbased on the resource allocation request amount of the terminalcollected for the time when the resource CBR reports are gathered andthe resource CBR value reported by the terminal. For example, the BS maycalculate respective averages with respect to the resource allocationrequest amount of the terminal collected for the time when the resourceCBR reports are gathered and the resource CBR value reported by theterminal. The BS may calculate respective averages with respect to theresource allocation request amount of the terminal collected for thetime when the resource CBR reports are gathered, the resource busyindicator reported by the terminal, and the resource non-busy indicatorreported by the terminal. Based on the resource CBR values calculatedfor all the zones, the BS may reconfigure the zone configuration in amanner that the resource is reduced with respect to the non-busy zone,and the resource is increased with respect to the busy zone.

FIG. 2C is a diagram illustrating an example of a BS operation forconfiguring/reconfiguring CBR based zone configuration according to anembodiment of the present disclosure.

Referring to FIG. 2C, at operation 1201, the BS configures the zoneconfiguration, and at operation 1202, the BS transmits the zoneconfiguration to the terminal. The zone configuration information mayinclude information that is necessary to acquire resource poolinformation allocated per zone and a CBR threshold value for triggeringa CBR state report for the zone. For example, the zone configurationinformation may include at least one of a width of a zone basic unit forderiving a zone ID, a length of the zone basic unit, a resource pool perzone ID, and a resource pool use CBR threshold value.

At operation 1203, the BS may receive a resource allocation request fromthe terminal. The resource request information of the terminal mayinclude at least one of a zone ID of the terminal, terminal location(location info), packet information (e.g., logical channel group,logical channel priority, and priority per packet) that the terminalintends to transmit using the resource, resource use amount requested bythe terminal, and resource use period requested by the terminal.

At operation 1204, the BS calculates a resource use amount requested bythe terminal with respect to the zone in which the terminal is located.Further, at operation 1205, the BS determines whether a time fortransmitting the zone configuration arrives. The time when the zoneconfiguration is to be transmitted may be determined to include a timethat is necessary to determine whether to reconfigure the zoneconfiguration and to reconfigure the zone configuration to betransmitted. If the time for transmitting the zone configuration doesnot arrive, the BS may continuously perform an operation of receivingthe resource allocation request from the terminal, and may calculate theresource use amount based on the received resource allocation request.

If the time for transmitting the zone configuration arrives, the BS, atoperation 1206, determines whether the resource CBR of the zone based onthe calculated resource use amount is equal to or higher than thresholdvalue A. If the resource CBR of the zone is equal to or higher thanthreshold value A, the BS, at operation 1207, may reconfigure the zoneconfiguration in a direction to increase a resource pool of each zone.As a method for increasing the resource pool of the zone, a method forincreasing a resource amount allocated to the zone or a method forincreasing the size of the zone may be included. Thereafter, the BSproceeds to operation 1202 to transmit the reconfigured zoneconfiguration to the terminal.

If the resource CBR of the zone is lower than threshold value A, the BS,at operation 1208, may determine whether the zone resource CBR is equalto or lower than threshold value B. If it is determined that the zoneresource CBR is equal to or lower than threshold value B, the BS, atoperation 1209, may reconfigure the zone configuration in a direction todecrease the resource pool of each zone. As a method for decreasing theresource pool of the zone, a method for decreasing a resource amountallocated to the zone or a method for decreasing the size of the zonemay be included. Thereafter, the BS proceeds to operation 1202 totransmit the reconfigured zone configuration to the terminal.

If the resource CBR of the zone is higher than threshold value B, the BSmay determine to maintain the current zone configuration. Thereafter,the BS proceeds to operation 1202 to transmit the existing zoneconfiguration to the terminal.

As described above with reference to FIG. 2C, it is first determinedwhether the resource CBR of the zone is equal to or higher thanthreshold value A and then it is determined whether the resource CBR ofthe zone is equal to or lower than threshold value B according to theresult of the determination. However, the present disclosure is notlimited thereto, but it may be first determined whether the resource CBRof the zone is equal to or lower than threshold value B and then it maybe determined whether the resource CBR of the zone is equal to or higherthan threshold value A according to the result of the determination.

FIG. 2D is a diagram illustrating another example of a BS operation forconfiguring/reconfiguring CBR based zone configuration according to anembodiment of the present disclosure.

Referring to FIG. 2D, at operation 1301, the BS configures the zoneconfiguration, and at operation 1302, the BS transmits the zoneconfiguration to the terminal. The zone configuration information mayinclude information that is necessary to acquire resource poolinformation allocated per zone and a CBR threshold value for triggeringa CBR state report for the zone. For example, the zone configurationinformation may include at least one of a width of a zone basic unit forderiving a zone ID, a length of the zone basic unit, a resource pool perzone ID, and a resource pool use CBR threshold value. At operation 1303,the BS may receive from the terminal a resource CBR report for the zonebeing monitored by the terminal.

Then, at operation 1304, the BS may determine whether a time fortransmitting the zone configuration arrives. The time when the zoneconfiguration is to be transmitted may be determined to include a timethat is necessary to determine whether to reconfigure the zoneconfiguration and to reconfigure the zone configuration to betransmitted. If the time for transmitting the zone configuration doesnot arrive, the BS may continuously perform an operation of receivingthe CBR for the zone from the terminal within the cell.

If the time for transmitting the zone configuration arrives, the BS, atoperation 1305, determines whether the resource CBR of the zone based onthe received CBR information for the zone received from the terminal isequal to or higher than threshold value A. If the resource CBR of thezone based on the received CBR information for the zone is equal to orhigher than threshold value A, the BS, at operation 1306, mayreconfigure the zone configuration in a direction to increase a resourcepool of each zone. As a method for increasing the resource pool of thezone, a method for increasing a resource amount allocated to the zone ora method for increasing the size of the zone may be included.Thereafter, the BS proceeds to operation 1302 to transmit thereconfigured zone configuration to the terminal.

If the resource CBR of the zone is lower than threshold value A, the BS,at operation 1307, may determine whether the zone resource CBR is equalto or lower than threshold value B. If it is determined that the zoneresource CBR is equal to or lower than threshold value B, the BS, atoperation 1308, may reconfigure the zone configuration in a direction todecrease the resource pool of each zone. As a method for decreasing theresource pool of the zone, a method for decreasing a resource amountallocated to the zone or a method for decreasing the size of the zonemay be included. Thereafter, the BS proceeds to operation 1302 totransmit the reconfigured zone configuration to the terminal. If theresource CBR of the zone is higher than threshold value B, the BS maydetermine to maintain the current zone configuration. Thereafter, the BSproceeds to operation 1302 to transmit the existing zone configurationto the terminal.

FIG. 2E is a diagram illustrating an example of a terminal operation forreporting a zone CBR according to an embodiment of the presentdisclosure.

Referring to FIG. 2E, at operation 1401, the terminal may receive zoneconfiguration information from the BS. The terminal may receive zoneconfiguration information from the BS. The zone configurationinformation may include information that is necessary to acquireresource pool information allocated per zone and a CBR threshold valuefor triggering a CBR state report of the zone. The CBR threshold valuefor triggering the CBR state report may include, for example, thresholdvalue A and threshold value B. Further, the zone configurationinformation may include at least one of a width of a zone basic unit forderiving a zone ID, a length of the zone basic unit, a resource pool perzone ID, and a resource pool use CBR threshold value. The resource pooluse CBR threshold value may include a threshold value used to measurethe resource pool use CBR.

At operation 1402, the terminal may determine the zone ID of theterminal from the zone configuration information, and thus may confirmthe resource pool allocated to the determined zone ID. At operation1403, the terminal may monitor the resource pool allocated to the zone.The terminal may measure the CBR of the resource allocated to the zonebased on the resource pool use CBR threshold value.

At operation 1404, the terminal may determine whether the CBR of theresource allocated to the zone is equal to or higher than thresholdvalue A. If the resource CBR of the zone is equal to or higher thanthreshold value, the terminal, at operation 1405, may configure CBRreport information for the resource of the zone to transmit the CBRreport information to the BS.

At operation 1406, the terminal may determine whether the CBR of theresource allocated to the zone is equal to or lower than threshold valueB. If the resource CBR of the zone is equal to or lower than thresholdvalue B, the terminal, at operation 1405, may configure the CBR reportinformation for the zone to transmit the CBR report information to theBS. If the resource CBR of the zone is higher than threshold value B,the terminal proceeds to operation 1403 to continuously performmonitoring of the resource pool allocated to its own zone ID.

As described above with reference to FIG. 2E, it is first determinedwhether the resource CBR of the zone is equal to or higher thanthreshold value A and then it is determined whether the resource CBR ofthe zone is equal to or lower than threshold value B according to theresult of the determination. However, the present disclosure is notlimited thereto, but it may be first determined whether the resource CBRof the zone is equal to or lower than threshold value B and then it maybe determined whether the resource CBR of the zone is equal to or higherthan threshold value A according to the result of the determination.

On the other hand, if the zone configuration information is receivedfrom the BS, the terminal may determine whether to change the zoneconfiguration information. If the zone configuration information ischanged, the terminal may replace the existing zone configuration by thenew zone configuration information, determine its own zone ID inaccordance with the new zone configuration information, and acquire theresource pool information allocated to its own zone. The zoneconfiguration signal may include message sequence number information sothat the terminal can grasp whether to change the zone configurationinformation.

FIG. 2F is a diagram illustrating a procedure of changing zone resourcepool configuration based on resource CBR according to an embodiment ofthe present disclosure. That is, FIG. 2F is a diagram illustrating aprocedure in which a BS configures zone configuration based on resourceCBR reported by a terminal.

Referring to FIG. 2F, a BS 1510 may transmit zone configurationinformation to a terminal (UE1) 1520 at operation 1501. In an embodimentof the present disclosure, the zone configuration information mayinclude information that is necessary to acquire resource poolinformation allocated per zone, and a CBR threshold value for triggeringCBR state report of the zone. Further, the zone configurationinformation may include at least one of a width of a zone basic unit forderiving a zone ID, a length of the zone basic unit, a resource pool perzone ID, and resource pool use CBR threshold value information. As anexample, in an LTE system, the zone configuration information may betransmitted through an SIB message. As another example, in an LTEsystem, the zone configuration information may be pre-configured in theterminal. As still another example, in an LTE system, the zoneconfiguration information may be transmitted through an RRC connectionreconfiguration message.

At operation 1502, the terminal 1520 may determine a zone ID of the zoneto which the terminal itself belongs based on the zone configurationinformation and its own location. At operation 1503, the terminal 1520may determine resource pool information corresponding to the zone IDbased on the zone configuration information. At operation 1504, theterminal 1520 may sense the resource pool to occupy a resource that isnecessary to transmit packets in the acquired resource pool. In theprocedure at operation 1504, the terminal 1520 may measure signalstrength of the resource pool. The signal strength of the resource poolmay be measured based on RSSI. The terminal 1520 may measure the CBR ofthe resource allocated to the zone through comparison of the measuredRSSI based signal strength with the resource pool use CBR thresholdvalue.

At operation 1505, the terminal 1520 may determine whether the CBR ofthe resource pool is equal to or higher than the CBR threshold value fortriggering the CBR state report. If it is determined that the CBR of theresource pool allocated to the zone ID to which the terminal 1520belongs is equal to or higher than the CBR threshold value fortriggering the CBR state report, the terminal 1520, at operation 1506,may transmit the CBR information to the BS 1510. The CBR information mayinclude at least one of the terminal (UE) ID, the terminal locationinformation, the zone ID information of the terminal, and the CBRmeasured by the terminal. Here, the location information of the terminalmay be described as information in Table 2. As an example, in an LTEsystem, the CBR information may be transmitted through a measurementreport message. As another example, in an LTE system, the CBRinformation may be transmitted through a UE information message. Asstill another example, in an LTE system, the CBR information may betransmitted through a sidelink UE information message.

TABLE 2 locationCoordinates-r10 CHOICE { ellipsoid-Point-r10 OCTETSTRING, ellipsoidPointWithAltitude-r10 OCTET STRING, ...,ellipsoidPointWithUncertaintyCircle-r11 OCTET STRING,ellipsoidPointWithUncertaintyEllipse-r11 OCTET STRING,ellipsoidPointWithAltitudeAndUncertaintyEllipsoid-r11 OCTET STRING,ellipsoidArc-r11 OCTET STRING, Polygon-r11 OCTET STRING } ,horizontalVelocity-r10 OCTET STRING, OPTIONAL, gnss-TOD-msec-r10 OCTETSTRING, OPTIONAL, LocationInfo field descriptions ellipsoidArc ParameterEllipsoidArc defined in 3GPP TS36.355. The first/leftmost bit of thefirst octet contains the most significant bit. ellipsoid-Point ParameterEllipsoid-Point defined in 3GPP TS36.355. The first/leftmost bit of thefirst octet contains the most significant bit.ellipsoidPointWithAltitude Parameter EllipsoidPointWithAltitude definedin 3GPP TS36.355. The first/leftmost bit of the first octet contains themost significant bit. ellipsoidPointWithAltitudeAndUncertaintyEllipsoidParameter EllipsoidPointWithAltitudeAndUncertaintyElllipsoid defined in3GPP TS36.355. The first/leftmost bit of the first octet contains themost significant bit. ellipsoidPointWithUncertaintyCircle ParameterEllipsoid-PointWithUncertaintyCircle defined in 3GP P TS36 .355. Thefirst/leftmost bit of the first octet contains the most significant bit.ellipsoidPointWithUncertaintyEllipse ParameterEllipsoidPointWithUncertaintyEllipse defined in 3GPP TS36.355. Thefirst/leftmost bit of the first octet contains the most significant bit.gnss-TOD-msec Parameter Gnss-TOD-msec defined in 3GPP TS36.355. Thefirst/leftmost bit of the first octet contains the most significant bit.horizontalVelocity Parameter HorizontalVelocity defined in 3GPPTS36.355. The first/leftmost bit of the first octet contains the mostsignificant bit. polygon Parameter Polygon defined in 3GPP TS36.355. Thefirst/leftmost bit of the first octet contains the most significant bit.

At operation 1507, the BS 1510 may determine whether to change the zonebased resource pool based on the CBR information received from theterminal 1520. Although FIG. 2F illustrates that the CBR information forthe resource pool is received from one terminal, the BS 1510 may alsoreceive the CBR information for the resource pool of the zone ID towhich the terminal belongs from one or more terminals. The BS 1510 maychange the zone configuration information based on the CBR informationreported by the terminal 1520. The zone configuration information thatcan be changed by the BS 1510 may include information that is necessaryto acquire the resource pool information allocated per zone and the CBRthreshold value for triggering the CBR state report for the zone.Further, the zone configuration information that can be changed by theBS 1510 may include at least one of a width of a zone basic unit, alength of the zone basic unit, a resource pool per zone ID, and aresource pool use CBR threshold value. For example, the BS may changethe amount of resource pool allocated to each zone ID while maintainingthe zone basic unit. As another example, the BS may change the width ofthe zone basic unit. As another example, the BS may change the width ofthe zone basic unit and the length of the zone basic unit. As anotherexample, the BS may change the resource pool use CBR threshold value. Atoperation 1508, the BS 1510 may transmit the changed zone configurationinformation to the terminal 1520. Next, an embodiment in which the BSchanges the zone configuration based on the channel CBR reported by theterminal will be described.

An example of the zone configuration information that is transmitted bythe BS through broadcast signaling or UE dedicated signaling is shown inTable 3, below.

TABLE 3 SL-ZoneConfig-r14 ::= SEQUENCE { zoneLength-r14 ENUMERATED {m5,m10,m20,m50,m100,m200,m500,spare1} OPTIONAL, -- Need OR zoneWidth-r14ENUMERATED { m5,m10,m20,m50,m100,m200,m500,spare1} OPTIONAL, -- Need ORzoneIdLongiMod-14 INTEGER (1..4) OPTIONAL, -- Need OR zoneIdLatiMod-r14INTEGER (1..4) OPTIONAL, -- Need OR }

FIG. 2GA is a diagram illustrating zone information example 1 accordingto a second embodiment of the present disclosure.

Referring to FIG. 2GA, the BS may transmit the zone configurationinformation that is configured as zone length of zone configuration=m5(5 meters), zone width=m5 (5 meters), zone ID longitude=3, and zone IDlatitude=6. The zone information configured based on the zoneconfiguration information may be configured as in FIG. 2GA.

FIG. 2GB is a diagram illustrating zone information example 2 accordingto a second embodiment of the present disclosure.

Referring to FIG. 2GB, if it is determined that the resource and channelCBR for zone ID 13 is higher than a predetermined threshold value, theterminal that belongs to the zone ID 13 may report the CBR for the zoneID 13 to the BS. The BS may receive may receive the CBR report from oneor more terminals using resources of the zone ID 13, and may determinezone configuration information change to reduce the CBR of the zone ID13 based on the CBR report. For example, the BS may determine to reducethe resource CBR by increasing the zone width, and the BS may configurezone length of zone configuration=m5 (5 meters), zone width=m10 (10meters), zone ID longitude=3, and zone ID latitude=3, and may transmitthe new zone configuration information. The zone information configuredbased on the new zone configuration information may be configured as inFIG. 2GB.

The terminal that has received the new zone configuration informationmay determine its own zone ID based on the zone configurationinformation. In this case, the zone configuration information mayinclude resource pool information allocated to each zone ID. Theterminal may acquire resource information corresponding to its own zonewith reference to the resource pool information corresponding to thezone ID.

In an embodiment of the present disclosure, if the CBR report isreceived from the terminal, the BS may instruct the terminal using anadjacent zone to report the CBR in order to adjust the zoneconfiguration. The CBR report instruction information may be transferredthrough a broadcast message, or may be transferred through a messagededicated to a specific terminal.

FIG. 2H is a diagram illustrating a procedure of changing zone resourcepool configuration based on resource CBR report according to anembodiment of the present disclosure.

A BS 1610 may transmit zone configuration information to terminals (UE1,UE2) 1620 and 1630 at operation 1601. The zone configuration informationmay include information that is necessary to acquire resource poolinformation allocated per zone, and a CBR threshold value for triggeringCBR state report of the zone. Further, the zone configurationinformation may include at least one of a width of a zone basic unit forderiving a zone ID, a length of the zone basic unit, a resource pool perzone ID, and resource pool use CBR threshold value information. As anexample, in an LTE system, the zone configuration information may betransmitted through an SIB message. As another example, in an LTEsystem, the zone configuration information may be pre-configured in theterminal. As still another example, in an LTE system, the zoneconfiguration information may be transmitted through an RRC connectionreconfiguration message.

At operation 1602, terminal (UE) 1 1620 and terminal (UE) 2 1630 maydetermine zone IDs of the zones to which the terminals themselves belongbased on the zone configuration information and their own locations. Theterminal 1 1620 and the terminal 2 1630 may determine resource poolinformation corresponding to the zone IDs based on the zoneconfiguration information. For example, at operation 1602, the terminal2 1630 may sense the resource pool to occupy a resource that isnecessary to transmit packets in the acquired resource pool. In theprocedure at operation 1602, the terminal 2 1630 may measure signalstrength of the resource pool. The signal strength of the resource poolmay be measured based on RSSI. The terminal 2 1630 may measure the CBRof the resource allocated to the zone through comparison of the measuredRSSI based signal strength with the resource pool use CBR thresholdvalue.

At operation 1603, the terminal 2 1630 may determine whether the CBR ofthe resource pool is equal to or higher than the CBR threshold value fortriggering the CBR state report. If it is determined that the CBR of theresource pool allocated to the zone ID to which the terminal 2 1630belongs is equal to or higher than the CBR threshold value fortriggering the CBR state report, the terminal 2 1630, at operation 1604,may transmit the CBR information to the BS 1610. The CBR information mayinclude at least one of the terminal 2 ID, location information of theterminal 2, the zone ID information of the terminal 2, and the CBRmeasured by the terminal. Here, the location information of the terminal2 may be described as information in Table 2. As an example, in an LTEsystem, the CBR information may be transmitted through a measurementreport message. As another example, in an LTE system, the CBRinformation may be transmitted through a UE information message. Asstill another example, in an LTE system, the CBR information may betransmitted through a sidelink UE information message.

If the CBR report is received from the terminal 2 1630, the BS 1610, atoperation 1605, may request the CBR report from the terminal belongingto an adjacent zone ID in order to determine the CBR of the zone IDadjacent to the zone of the terminal 2 1630. The BS 1610 may instructthe terminal 1 1620 that uses the resource pool of an adjacent zone IDto report the CBR of the adjacent zone ID. Further, at operation 1606,the terminal 1 1620 may report the CBR of the resource pool of thecorresponding zone ID to the BS 1610. The CBR report request messagetransmitted to the terminal that uses the adjacent zone may betransmitted to a specific terminal through dedicated signaling. Asanother example, the CBR report request message transmitted to theterminal using the adjacent zone may be transmitted to a certainterminal that belongs to the adjacent zone through broadcast signaling.The broadcast signaling may include target zone ID information to whichthe CBR is to be reported. The CBR report request message may includeCBR threshold value information that the terminal 1 1620 or a certainterminal belonging to the adjacent zone will use as a basis in reportingthe resource pool CBR of the adjacent zone. Based on the CBR thresholdvalue information, the terminal 1 1620 may report that the CBR of theresource pool of the zone of the terminal 1 1620 is lower than, equalto, or higher than the threshold value. Further, the terminal 1 1620 mayreport the CBR of the resource pool of the zone as an RSSI value.

At operation 1607, the BS 1610 may determine whether to change the zonebased resource pool based on the CBR information received from theterminal 2 1630 and the terminal 1 1620. In an embodiment of FIG. 2H, itis illustrated that the CBR information for the resource pool isreceived from two terminals. However, the present disclosure is notlimited thereto, but the BS 1610 may also receive from two or moreterminals the CBR information for the resource pool of the zone ID towhich the respective terminals belong. The BS 1610 may change the zoneconfiguration information based on the CBR information reported by theterminal 2 1630 and the terminal 1 1620. The zone configurationinformation that can be changed by the BS 1610 may include informationthat is necessary to acquire the resource pool information allocated perzone, and the CBR threshold value for triggering the CBR state report ofthe zone. Further, the zone configuration information that can bechanged by the BS 1610 may include at least one of the width of a zonebasic unit, the length of the zone basic unit, the resource pool perzone ID, and the resource pool use CBR threshold value. As an example,the BS may change the amount of the resource pool allocated to each zoneID while maintaining the zone basic unit. As another example, the BS maychange the width of the zone basic unit. As another example, the BS maychange the width of the zone basic unit and the length of the zone basicunit. As another example, the BS may change the resource pool use CBRthreshold value. At operation 1608, the BS 1610 may transmit the changedzone configuration information to the terminal 2 1630.

From the foregoing, a certain terminal 1 1620 belonging to the adjacentzone has been exemplified. According to various embodiments of thepresent disclosure, the terminal 1 1620 may correspond to a terminalpre-configured to report the resource pool CBR of each zone.

According to another embodiment of the present disclosure, the BS mayperiodically request the CBR report from the terminal. The terminal maycorrespond to the UE mounted on a vehicle or the UE mounted on a fixedRSU. The terminal that will periodically transmit the CBR report may bepreregistered in the BS. If the terminal designated for the purpose ofthe CBR report deviates from the BS area, the BS may designate anotherterminal to periodically transmit the CBR report. Based on the periodinformation configured by the BS, the terminal may report the resourceof the zone used by the terminal itself and channel CBR based on theperiod information configured by the BS. Based on the resource andchannel CBR information periodically received from the terminal, the BSmay adjust the zone configuration or may transmit the reconfigured zoneconfiguration information.

FIG. 2I is a diagram illustrating a procedure of changing zone resourcepool configuration based on periodic resource CBR report according to anembodiment of the present disclosure.

Referring to FIG. 2I, a BS 1710 may transmit zone configurationinformation to a terminal (UE2) 1720 at operation 1701. The zoneconfiguration information may include information that is necessary toacquire resource pool information allocated per zone. Further, the zoneconfiguration information may include at least one of a width of a zonebasic unit for deriving a zone ID, a length of the zone basic unit, aresource pool per zone ID, resource pool use CBR threshold value, andperiod information for reporting the resource pool CBR. As an example,in an LTE system, the zone configuration information may be transmittedthrough an SIB message. As another example, in an LTE system, the zoneconfiguration information may be pre-configured in the terminal. Asstill another example, in an LTE system, the zone configurationinformation may be transmitted through an RRC connection reconfigurationmessage.

At operation 1702, the terminal 1720 may determine a zone ID based onthe zone configuration information and its own location. At operation1703, the terminal 1720 may determine resource pool informationcorresponding to the zone ID based on the zone configurationinformation. At operation 1704, the terminal 1720 may acquire periodinformation for reporting the CBR for the resource pool corresponding toits own zone ID. Based on the acquired period information, the terminal1720, at operation 1705, may sense the resource pool corresponding tothe zone ID, and may report the CBR for the resource pool to the BS1710. For example, the terminal 1720 may measure signal strength of theresource pool. The signal strength of the resource pool may be measuredbased on RSSI. The terminal 1720 may measure the CBR of the resourceallocated to the zone through comparison of the measured RSSI basedsignal strength with the resource pool use CBR threshold value. Thesignal strength of the resource pool may be measured based on an energylevel. The terminal 1720 may sense the zone resource pool CBR situation,and at operation 1706, may report the zone resource pool CBR situationto the BS 1710.

At operation 1707, the BS 1710 that has received the CBR for theresource pool from the terminal 1720 may determine whether it isnecessary to change the zone configuration. If it is not determined thatthe zone resource CBR based on the CBR report is equal to or higher thanthreshold value A or equal to or higher than a threshold value X, the BS1710 may maintain the existing zone configuration. If it is determinedthat the zone resource CBR is equal to or higher than threshold value A,equal to or higher than threshold value B, or equal to or higher thanthe threshold value X based on the CBR report from the terminal 1720,the BS 1710 may determine that a new zone configuration is necessarybased on the CBR report from the terminal 1720, and may configure thenew zone configuration to be transmitted to the terminal 1720 atoperation 1708. The zone configuration transmitted at operation 1708 mayinclude new zone configuration information or new CBR thresholdinformation. The terminal that has received the changed zoneconfiguration information may determine its own zone ID based on thezone configuration, and may acquire the resource pool informationcorresponding to the zone ID.

FIG. 2J is a diagram illustrating an example of zone resource pooloperation based on CBR report according to an embodiment of the presentdisclosure.

Referring to FIG. 2J, at operations 1801 and 1802, UE1 1820 and UE2 1830may report measured resource CBR to a BS 1810. At operation 1803, the BS1810 may determine whether the CBR of a resource pool of each zone isequal to or higher than a threshold value based on the resource CBRreport received from the UE1 1820 and UE2 1830. If it is determined thatthe CBR of the resource pool of the zone is equal to or higher than thethreshold value, the BS 1810 may change the configuration for the zone.At operations 1804 and 1805, the BS 1810 may transmit the changed zoneconfiguration information to the terminals. The zone configurationchange may include a change of a zone grid. For example, if a largenumber of vehicle terminals use resources in a specific zone to which aspecific grid configuration is applied, the grid configuration maybecome closer, and thus collision can be reduced in selecting theresources using the same pools in a smaller unit area. In addition, theBS 1810 may instruct UE1 1820 and UE2 1830 to adjust transmission powerfor the corresponding resource pools simultaneously with changing thezone grid. That is, the zone configuration information may include zonegrid information and transmission power information. The transmissionpower information for the zone resource pool may be transmitted to theterminals in the BS cell through a system information broadcastingmessage transmitted by the BS 1810 or dedicated signaling directlytransmitted to the terminals. If new zone configuration informationtransmitted by the BS 1810, that is, zone grid information andtransmission power information for the resource pool, is received, theterminals 1820 and 1830, at operations 1806 and 1807, may determineagain their own zones based on the received information, and may acquirethe resource pool information corresponding to the zone. Further, theterminals may perform data transmission using the resource poolinformation and the corresponding transmission power information.

On the other hand, although it is assumed that any terminal thatsupports vehicle communication (e.g., third generation partnershipprogram (3GPP) V2X communication) can report the resource CBR accordingto the above-described embodiment, the present disclosure can also beapplied even in the case where the BS designates a specific terminal forthe purpose of reporting the resource CBR. The terminal designated forthe purpose of reporting the resource CBR may be a terminal mounted on avehicle, a terminal mounted on a road side unit (RSU), or a terminalmounted on a pedestrian, driver, or passenger.

As another embodiment other than the embodiment in which the resourceCBR is applied to the case of the zone based resource pool operation,the resource CBR may be applied to a resource pool (V2V resource pool)used for direct communication between vehicle UEs, a resource pool(P2V/V2P resource pool) used for direct communication between pedestrianUE and vehicle UE, or a resource pool (V2I/I2V resource pool) used fordirect communication between vehicle UE and an RSU. The resource poolmay correspond to a resource pool that the vehicle UE, the pedestrianUE, or the RSU uses for the purpose of transmission (Tx). The resourcepool may correspond to the resource pool that the vehicle UE, thepedestrian UE, or the RSU uses for the purpose of reception (Rx). Theresource CBR configuration information applied to the resource pool usedfor direct communication between the vehicle UEs, the resource pool usedfor direct communication between the pedestrian UE and the vehicle UE,or the resource pool used for direct communication between the vehicleUE and the RSU may be provided to the vehicle UE, the pedestrian UE, andthe RSU through the BS.

The resource CBR configuration information may include a CBR thresholdvalue for triggering the resource CBR state report. According to variousembodiments of the present disclosure, the CBR threshold value mayinclude reference threshold value A determined to have high resource CBRand reference threshold value B determined to have low resource CBR.Further, the CBR threshold value may be used to determine the resourceCBR for the resource pool used by the UE and to report the determinedresource CBR to the BS. The resource CBR information reported by theterminal may be used for the BS to reconfigure the resource pool managedby the BS and for control of transmission parameters (e.g., Tx resourcepool, Rx resource pool, transmission power, and modulation and codingscheme (MCS) level) in the resource pool.

The CBR threshold value may be differently configured per resource pooltype. That is, the CBR threshold values of the resource pool used by thepedestrian UE, the resource pool used by the vehicle UE, and theresource pool used by the RSU may be configured equally or differently,and the CBR threshold configuration information per resource pool typemay be transferred from the BS to the UE through signaling or may bepre-configured to the UE. For example, the CBR threshold values appliedto an inter-public land mobile network (PLMN) resource pool type and anintra-PLMN resource pool type may be equally or differently configured.

As another embodiment, the CBR threshold values may be differentlyconfigured per packet priority. That is, in the case of using a servicehaving high packet priority, a high CBR threshold value may be applied,whereas in the case of using a service having low packet priority, a lowCBR threshold value may be applied. The CBR threshold valueconfiguration based on the packet priority may be determined in adirection in which a service having high packet priority can be servicedat maximum speed and with high reliability.

As still another embodiment, the CBR threshold values may be configuredequally or differently in accordance with a case where the UE performsV2X operation in an idle mode or a case where the UE performs V2Xoperation in a connected mode. For example, the CBR threshold value inan idle mode may be configured in a direction in which the idle mode UEmaintains the smaller number of times of transmission of the resourceCBR situation report as compared with the connected mode UE. The CBRthreshold values may be equally or differently configured per zone. Forexample, the CBR threshold value for the zone in which a large number ofUEs are distributed may be configured to be smaller than the CBRthreshold value for the zone in which a small number of UEs aredistributed.

As still another embodiment, the CBR threshold values may be configuredwith the same value or different values per carrier frequency.

Next, according to various embodiments of the present disclosure, aprocedure in which a pedestrian terminal performs resource CBR reportwill be described. The pedestrian terminal may or may not perform theresource CBR report operation based on the terminal location or aresidual battery level of the terminal. That is, if it is determinedthat the pedestrian terminal is located indoors or is located in a safearea from vehicles, the pedestrian terminal may not perform the resourceCBR report operation according to an embodiment of the presentdisclosure. If it is determined that the pedestrian terminal has aresidual battery level that is lower than a specific threshold value, itmay not perform the resource CBR report operation according to theembodiment of the present disclosure.

FIG. 2K is a diagram illustrating a terminal operation for determiningwhether to perform a channel measurement operation for determiningresource CBR by checking the state of a pedestrian UE according to anembodiment of the present disclosure. Operations described hereinaftermay not be all essential, but at least one operation may be omitted.

Referring to FIG. 2K, at operation 1910, a terminal may receive aresource CBR report configuration message from a BS. The resource CBRreport configuration message may be transferred through systeminformation or dedicated signal. At operation 1920, the terminal maycheck the terminal state.

At operation 1930, the terminal may determine whether the resource CBRcan be checked through the confirmed terminal state and/or the resourceCBR report configuration message. For example, if the resource CBRreport configuration message is received, the terminal can determinewhether the resource CBR can be checked. If the resource CBR reportconfiguration message is received from the BS, the terminal maydetermine that it is in a resource CBR checkable state.

As another example, the terminal may receive the resource CBR reportconfiguration message, check the terminal state, and determine whetherthe resource CBR can be checked. The terminal state may be determined bychecking the residual battery level of the terminal, checking theterminal location, or checking a case where the terminal is in an idlemode. The terminal may determine whether the resource CBR can be checkedafter checking the terminal state as in the above example, the terminalmay confirm that it is in a resource CBR checkable state if the residualbattery level of the terminal is higher than a specific threshold value,if the terminal is located adjacent to a road, or if the terminal is notin an idle mode. Whether the terminal is located adjacent to a road maybe determined using, for example, terminal location information and MAPinformation.

If the terminal is in a resource CBR checkable state, the terminal, atoperation 1940, may measure a channel. For example, the terminal maydetermine a resource busy state through measurement of the signalstrength of a reference signal received in the resource pool.

FIG. 2L is a diagram illustrating a terminal operation method forreporting resource CBR report according to an embodiment of the presentdisclosure.

Referring to FIG. 2L, the terminal may measure an effective channelsituation and may report resource CBR to the BS. At operation 2010, theterminal may perform a channel measurement operation for a resourcepool.

If a channel value (e.g., signal strength) for the resource pool isdetermined through the channel measurement, the terminal, at operation2020, may check the resource CBR state by comparing the determinedchannel value with a condition value included in a resource CBRconfiguration message. At operation 2030, the terminal may check whetherto satisfy the resource CBR report condition by comparing the channelvalue with the condition value. If the resource CBR report condition isnot satisfied, the terminal proceeds to operation 2050 and canimmediately report the resource CBR to the BS. Further, the terminal maycompare a channel value with a condition value, and if the resource CBRreport condition is satisfied, it may check whether the resource CBRsituation is effective as at operation 2040. Further, only in the casewhere the resource CBR situation is determined to be effective, theterminal may report the resource CBR to the BS as at operation 2050.

For example, if the channel signal strength measured by the terminal islower than a condition value B or is higher than a condition value Areceived from the BS, the terminal may check whether the resource CBRsituation is effective. For example, if the channel signal strengthmeasured by the terminal is higher than a condition value X receivedfrom the BS, the terminal may check whether the resource CBR situationis effective.

As an example of whether the resource CBR situation is effective, theterminal may compare the channel measurement value with the resource CBRcondition value, and if time when the resource CBR condition issatisfied is larger than the value configured from the BS, the terminaldetermines that the resource CBR situation for the resource (channel) iseffective, and may report the resource CBR to the BS. Further, if theresource of the terminal is not changed (e.g., the same resource pool)while the resource CBR condition is satisfied through comparison of thechannel measurement value with the resource CBR condition value, theterminal may determine that the resource CBR situation is effective, andmay report the resource CBR to the BS. If the resource of the terminalis changed (e.g., zone change) while the resource CBR condition issatisfied through comparison of the channel measurement value with theresource CBR condition value, the terminal may initialize themeasurement result of the resource CBR of the terminal without reportingthe resource CBR to the BS. As another example, the terminal may comparethe channel measurement value with the resource CBR condition value, andif it is determined that the resource CBR condition is satisfied and theresource CBR report transmission limit time is not configured, theterminal may report the resource CBR to the BS. Further, the terminalmay compare the channel measurement value with the resource CBRcondition value, and if it is determined that the resource CBR conditionis satisfied and the resource CBR report transmission limit time isconfigured, the terminal may perform channel measurement until theresource CBR report transmission limit time is released withoutreporting the resource CBR to the BS.

The configuration information of the resource CBR report or the resourceCBR report may be transmitted through a media access control (MAC)control element (MAC sub-layer control signal). For example, in an LTEsystem, if the BS notifies the terminal of whether to transmit theresource CBR report and resource CBR configuration information throughthe MAC CE, the terminal may transfer the resource CBR report to the BSusing the resource CBR MAC CE. As the MAC CE, the BS may transmit achannel busy ratio (CBR) report configuration MAC control element. Asthe MAC CE, the terminal may report the channel busy ratio reportconfiguration MAC control element. If the channel busy ratio reportconfiguration MAC control element is transmitted as the MAC CE, it mayinclude terminal information (e.g., UE ID), channel information (e.g.,channel busy percentage) or local information (e.g., zone ID), and thecorresponding information may be expressed as a value or may be indexedto be displayed.

FIG. 2M is a diagram illustrating a terminal operation for performingresource CBR report using resource configuration information for apacket or a service having high priority according to an embodiment ofthe present disclosure.

Referring to FIG. 2M, at operation 2110, the terminal may receiveresource CBR report configuration transmitted by the BS. The resourceCBR report configuration may configure, for example, a resource CBRmeasurement period of a channel, a resource to be measured, and aresource CBR threshold value. Further, at operation 2120, the terminalmay receive resource configuration information having high priority inaddition to the resource CBR report configuration.

For example, in an LTE system, the terminal may receive resource CBRreport configuration information per packet priority or service priorityfor transmitting a V2X message from the BS. As another example, theterminal may receive semi persistence scheduling (SPS) configurationinformation for transmitting the V2X message from the BS.

At operation 2130, the terminal may change the resource CBR reportconfiguration information using the resource CBR report configurationinformation per packet priority or service priority. The resource CBRreport configuration information per packet priority or service prioritymay include resource pool information to perform the resource CBR reportper packet priority or service priority, resource CBR thresholdinformation, transmission power during packet transmission from theresource pool, and MCS level during the packet transmission.

The terminal may change the resource CBR report configuration using theSPS configuration information. The SPS configuration information mayinclude resource CBR threshold value information that is necessary toperform the resource CBR report for the SPS resource pool, transmissionpower during the packet transmission from the SPS resource pool, MCSlevel during the packet transmission, resource CBR measurement period,and resource CBR measurement period. For example, if data transmissionperiod among the SPS configuration information is shorter than theresource CBR measurement period, the resource CBR measurement period maybe change to the data transmission period. Further, if the datatransmission period among the SPS configuration information is shorterthan the resource CBR measurement period, the resource CBR measurementperiod may be changed to the data transmission period. Further, usingimplicit release information among the SPS configuration information, itmay be determined how long the resource CBR measurement and transmissionperiod change continue. For example, if there is not the SPS datatransmission (using implicit release information) for a predeterminedtime after the CBR measurement period of the terminal is changed usingthe SPS configuration information, the SPS is released, and in thiscase, the CBR measurement period changed by the terminal may be changedto the existing value being used.

According to an embodiment of the present disclosure, the resource CBRmay be reported through a PC5 packet.

This may be applied in relation to the embodiment for the resource CBRoperation for the resource pool used for direct communication betweenthe UEs and the resource pool used for direct communication between theUE and the RSU during performing direct communication between UEs ordirect communication between the UE and the RSU. The UE may includevehicle UE and pedestrian UE. The UE may determine the CBR for theresource pool by performing channel measurement for the resource pool tobe used for PC5 packet transmission. The UE may include the measuredresource pool CBR information in the PC5 packet to be transmitted. Asanother example, the UE may include the measured resource pool CBRinformation in scheduling signal (e.g., SA) for PC5 packet transmission.The PC5 packet and the scheduling signal for the PC5 packet transmissionmay include resource pool information and CBR information for theresource pool.

If the CBR information for the resource pool is received, thedestination UE or RSU that receives the PC5 packet may reserve the useof the resource pool or may determine the use of the resource pool basedon the CBR level. As another example, if the CBR information for theresource pool is received, another UE or RSU that receives thescheduling signal for the PC5 packet transmission may reserve the use ofthe resource pool or may determine the use of the resource pool based onthe CBR level. The other UE or RSU that receives the PC5 packet and thescheduling signal for the PC5 packet transmission may transfer the CBRinformation for the resource pool to the BS. The BS that has receivedthe CBR information for the resource pool through the other UE or RSUmay adjust the resource pool information to be used for the PC5 packettransmission and reception.

FIG. 2N is a diagram illustrating a method for V2X-UE to transmitresource CBR in a connectionless state according to an embodiment of thepresent disclosure. The connectionless state may be a state where an RRCconnection with the BS is not maintained, that is, an RRC-idle state. Inthe drawing, V2X-UE A is in an RRC-connected state, and V2X-UE B, V2X-UEC, and V2X-UE D are in an RRC-idle state. The terminals in theRRC-connected state may transmit and receive a V2X service message usingthe resource pool directly scheduled by the BS or a V2X resource of mode4 type (mode in which the UE selects the resource pool at its discretionregardless of the BS) in accordance with the configuration of the BS.The terminals in the RRC-idle state may transmit and receive a V2Xservice message using the V2X resource of the mode 4 type (mode in whichthe UE selects the resource pool at its discretion regardless of the BS)in accordance with the configuration of the BS. The UE using the mode 4resource may measure the resource CBR for the mode 4 resource pool. Asdescribed above, the configuration information for measuring theresource CBR for the mode 4 resource may be transmitted by the BS in abroadcast method or in a dedicated signaling method to the terminal. Theresource CBR configuration information for the mode 4 resource mayinclude threshold values A and B for the resource CBR report, thresholdvalue X, and resource CBR report period information.

Referring to FIG. 2N, if it is determined that the resource CBR for themode 4 type V2X resource is busy, the terminals in an RRC-connectedstate may report the resource CBR for the V2X resource to the BS. If itis determined that the resource CBR for the mode 4 type V2X resource isbusy, the terminals in the RRC-idle state may notify a neighborRRC-connected terminal of the V2X resource CBR information for the mode4 type using the V2X message transmitted using the mode 4 resource. TheRRC-connected terminal may include vehicle UE, pedestrian UE, or RSU.

The V2X message transmitted by the terminal in the RRC-idle state mayrequest the RRC-connected terminal to transfer the measurement result ofthe resource CBR for the mode 4 resource to the BS (1). In an embodimentof the present disclosure, the message for requesting to transfer themeasurement result of the resource CBR for the mode 4 resource may use aCBR relay-request message. The CBR relay-request message may include themode 4 resource pool and measured resource CBR information for the mode4 resource pool.

If a CBR relay-request message is received, the RRC-connected terminal(V2X-UE A) may relay the resource CBR message to its own BS (2). If theresource CBR relay message (CRB relay) is received from theRRC-connected terminal (V2X-UE A), the BS may reconfigure the V2Xresource of the mode 4 type in accordance with the resource CBR valueincluded in the message.

The CBR relay message may include the mode 4 resource pool and measuredresource CBR information for the mode 4 resource pool. For example, ifit is determined that the mode 4 resource pool is busy based on theresource CBR information for the mode 4 resource pool included in theCBR relay message, the BS may configure the mode 4 type V2X resourcepool having a size that is larger than that at the present, and maytransmit the adjusted mode 4 type resource pool information (3). If itis determined that the mode 4 resource pool is not busy based on theresource CBR information for the mode 4 resource pool included in theCBR relay message), the BS may configure the V2X resource pool for themode 4 type to be smaller than that at the present, and may transmit theadjusted mode 4 type resource pool information (3). The V2X resourceconfiguration information for the mode 4 type notified by the BS may betransmitted by broadcast, and may be transmitted by a terminal-orientedmessage (dedicated signaling). The other RRC idle terminal (e.g., V2X-UEC or V2X-UE D) that has received the CBR relay-request message sent fromthe RRC idle terminal (e.g., V2X-UE B) may not transmit the CBRrelay-request message for a predetermined time after receiving the CBRrelay-request message.

On the other hand, if the terminal that uses the mode 4 resource pooldeviates from a BS cell area, it may not receive the adjusted mode 4resource pool from the BS, and may not receive the CBR configurationinformation for the mode 4 resource pool from the BS. The terminal thatdeviates from the base cell area may receive the CBR configurationinformation for the mode 4 resource pool or the adjusted mode 4 resourcepool information from another terminal or RSU located in the BS cellarea. Further, the other terminal or RSU located in the BS cell area maytransfer the resource CBR report for the mode 4 resource pool that istransmitted by the terminal that deviates from the BS cell area to theBS.

FIG. 2O is a diagram illustrating a method for V2X-UE to transmitresource CBR for inter-PLMN resource according to an embodiment of thepresent disclosure.

Referring to FIG. 2O, in the drawing, V2X-UE A is a terminal in anRRC-connected state that belongs to PLMN A, and V2X-UE B and V2X-UE Care RRC-idle terminals that belong to PLMN A. It is assumed that theterminals in the RRC-idle state has inter PLMN V2X resources transmittedfrom the BS and are in use of inter PLMN V2X services. The BS maytransmit the resource CBR threshold value for the PLMN resource pool andresource CBR measurement configuration information to the terminals. Theresource CBR threshold value for the PLMN resource pool and resource CBRmeasurement configuration information may be transmitted by the BS in abroadcast method or in a dedicated signaling method to the terminal. Theresource CBR threshold value for the PLMN resource pool and resource CBRmeasurement configuration information may include a PLMN resource poolthat will measure and report the resource CBR threshold value, CBRreport threshold value A and threshold value B for the pool resource,threshold value X information, and resource CBR measurement reportperiod.

If it is determined that the V2X resource CBR for PLMN based on theresource CBR measurement configuration information is busy, theterminals in the RRC-idle state may notify neighbor RRC-connectedterminal of the V2X resource CBR for PLMN A using the inter PLMN V2Xresource for PLMN A or mode 4 resource. The terminal in the RRC-idlestate may request the RRC-connected terminal to relay the V2X resourcefor the PLMN A or resource CBR information for mode 4 resource to the BS(1). In this case, the CBR relay-request message sent to the BS mayinclude the V2X resource CBR for the PLMN A or the resource CBRinformation for mode 4 resource. If the CBR relay-request message isreceived, the RRC-connected terminal (V2X-UE A) may transfer theresource CBR message (CBR relay) to its own BS (2). If the resource CBRrelay message (CBR relay) is received from the terminal, the BS maycheck the V2X resource CBR for the PLMN A included in the message or themode 4 resource CBR, and in accordance with the resource CBR value forthe PLMN A or the mode 4 resource CBR value, the BS may determine theresource reconfiguration for the inter-PLMN. If it is determined thatthe resource reconfiguration for the inter-PLMN is necessary, the BS mayreconfigure the resource pool for PLMN A, and may transfer the poolreconfiguration information for the PLMN A to another PLMN BS. If it isdetermined that the resource pool reconfiguration for the PLMN B isnecessary due to the resource pool reconfiguration for the PLMN A, theBS A and the BS B may additionally exchange information for the resourcereconfiguration for the inter-PLMN between them.

For example, if it is determined that the resource for the PLMN A isbusy based on the inter-PLMN V2X resource CBR information for the PLMN Aincluded in the CBR relay message, the BS A may configure the inter-PLMNV2X resource for PLMN A having a size that is larger than that at thepresent, and may transmit the inter-PLMN V2X resource change informationfor the PLMN A to the BS B (3). Here, as a method and procedure oftransmitting to another PLMN BS, signaling method and procedure betweenBSs that belong to the other PLMN may be used. If it is determined thatthe resource for the PLMN A is not busy based on the inter-PLMN V2Xresource CBR information for the PLMN A included in the CBR relaymessage, the BS A may configure the inter-PLMN V2X resource for PLMN Ahaving a size that is smaller than that at the present, and may transmitthe inter-PLMN V2X resource change information for the PLMN A to the BSB (3). The BS B that has received the inter-PLMN resourcereconfiguration message from the BS A may transmit the V2X resource poolinformation of the adjusted PLMN A to the terminals located in its owncell.

The BS B may reconfigure the inter-PLMN resource based on the resourcepool adjustment information of the PLMN A received from the BS A (4). Inthe drawing, in the case of PLMN A, the inter-PLMN resource is busy,whereas in the case of PLMN B, the inter-PLMN resource is not busy.Accordingly, the resource of PLMN A may be greatly changed, and theresource of PLMN B may be slightly changed. In contrast, in the case ofPLMN A, the inter PLMN resource is not busy, whereas in the case of PLMNB, if the inter PLMN resource is busy, the resource of the PLMN A may beslightly changed, and the resource of the PLMN B may be greatly changed.The PLMN A BS that has received the inter PLMN resource reconfigurationresponse message from the BS B may notify the terminals located in theirown cell of the adjusted inter-PLMN resource information (5). Theinter-PLMN V2X resource configuration information notified by the BS maybe transmitted through broadcasting or terminal-oriented message(dedicated signaling). The terminal located in the RRC connected may bevehicle UE, pedestrian UE, or RSU. Another RRC idle terminal (e.g.,V2X-UE C or V2X-UE D) that has received the CBR relay-request messageincluding the resource CBR information for the same PLMN V2X resourcemay not transmit the CBR relay-request message for a predetermined time.

If an LTE serving cell has a band that supports or does not support theV2X service, the LTE serving cell may perform signaling whether toperform resource allocation of the V2X service band. The signaling fornotifying whether the band of the LTE serving cell supports resourceallocation for the V2X service may be transmitted in the broadcastmethod. Further, the signaling transmitted in the broadcast method maybe used for the purpose of notifying whether the band of the adjacentLTE cell supports resource allocation for the V2X. Further, thesignaling for notifying whether the band of the serving LTE cell throughthe band of the adjacent LTE cell may support the resource allocationfor the V2X service may be transmitted through UE dedicated signaling.If the LTE cell performs band resource allocation for the V2X service,the band for the V2X service may correspond to the service band of theLTE cell, or may correspond to another intelligent transportationsystems (ITS) service band other than the service band of the LTE cell.

In the present disclosure, a case where V2X service is provided in anITS service band other than the service band of an LTE cell based onFIG. 2P will be described. FIG. 2P is a diagram illustrating a casewhere a serving BS transfers to a broadcasting channel informationindicating that the serving BS can perform ITS band resource allocationalthough a serving BS does not have the ITS frequency band according toan embodiment of the present disclosure.

Referring to FIG. 2P, at operation 2201, the serving BS 2210 maytransfer V2X resource pool for another service frequency band other thanits own service band and resource CBR information through thebroadcasting channel. The information may include information of thecorresponding ITS frequency band, Tx/Rx resource pool information forrespective ITS frequencies, and related CBR threshold value information.

At operation 2202, the terminal 2220 may measure a resource pool of theITS frequency band allocated thereto based on the received information,a resource pool to be used by itself, or CBR (resource CBR) of thecorresponding ITS frequency band. At operation 2203, the terminal 2220may check whether the measured CBR meets the CBR report condition, andif the CBR meets the CBR report condition, it may determine to transmitthe corresponding CBR value and the resource pool information to theserving BS 2210. At operation 2204, the terminal may determine totransmit to the serving BS 2210 the corresponding CBR value and theresource pool information. At operation 2204, the terminal 2220transmits the measured CBR value and the resource pool information. Atoperation 2205, the serving BS 2210 may change the resource pool of theITS frequency band allocated to the terminal based on the CBR value ofthe ITS frequency band and the resource pool information received fromnot only the terminal 2220 but also other terminals to another resourcepool, or may differently change the resource pool configuration of theITS frequency band. AT operation 2206, the serving BS 2210 may transferthe changed information to the dedicated or broadcasting channel. Atoperation 2207, the terminal 2220 may use the Tx/Rx pool changed basedon the transferred information.

As described above, FIG. 2Q exemplifies an operation in the case wherethe serving BS cannot perform cross-carrier resource allocationaccording to an embodiment of the present disclosure.

Referring to FIG. 2Q, in this case, a terminal 2340 first grasps that aserving cell does not indicate the cross-carrier resource allocationthrough a broadcasting channel, and at operation 2301, may search forand check whether a cell exists through searching for the ITS frequencyband. If a cell that satisfies a specific condition is searched for inthe ITS frequency band (in this case, cell search based on the signalstrength, such as S-measure, may be used), the terminal 2340, atoperation 2302, may read the broadcasting channel of the correspondingcell, and may receive Tx/Rx pool information and threshold valueinformation for CBR report of the corresponding pool. In this case, theinformation may be transmitted through the broadcasting channel. Thebroadcasting channel may include an ID of the corresponding cell. Theterminal 2340 that has received the information, at operation 2303, mayuse the Tx pool, and may measure the CBR for the Tx pool. At operation2304, if the CBR report condition is satisfied, the terminal maydetermine to report the resource CBR for the Tx pool. At operation 2305,the terminal 2340 transmit the resource CBR information to the servingBS 2320 that does not support the ITS band. In this case, the reportedresource CBR information may include a measured CBR value andcorresponding resource pool information, ITS serving cell ID, and ITSserving cell band (carrier frequency band) information.

If the CBR report for the ITS band if the terminal 2340 is received, theserving BS 2320, at operation 2306, transfers the CBR information andthe resource pool information measured by the terminal to a neighbor BS2330 that support the corresponding ITS band. The terminal resource CBRreport and resource pool information between the serving BS 2320 and theITS band BS 2330 may be transferred using an X2 interface.

At operation 2307, the ITS band BS 2330 may change the resource poolthat is given to the corresponding terminal based on the CBR relatedinformation transmitted from not only the terminal 2340 but also otherterminals, or may increase or decrease the resource structure of thewhole pool. At operation 2308, the ITS band BS 2330 may transfer thechanged resource pool information to the serving BS 2320 through the X2interface. Further, the ITS band BS 2330 may not transmit the changedresource pool information to the serving BS 2330, but may broadcast thesame only in its own cell. At operation 2309, the serving BS 2320 thathas received the changed resource pool information of the ITS band fromthe ITS band BS 2330 may transfer the corresponding information to theterminal 2340 through dedicated signaling or the broadcasting channel.For example, a command for changing the resource pool of a specificterminal may be transferred through the dedicated signaling, and thechanged structure information of the specific resource pool of the ITSband may be transferred through the broadcasting channel. At operation2310, the terminal 2340 that has received the information may performV2X communication based on the Tx resource pool corresponding to theterminal itself.

FIG. 2R is a diagram illustrating a process in which a neighbor celldoes not transfer information to a serving cell after controllingresources, but a terminal obtains the information by monitoring theneighbor cell directly through a broadcasting channel according to anembodiment of the present disclosure.

Referring to FIG. 2R, the terminal 2430 may grasp that the serving celldoes not indicate cross-carrier resource allocation through abroadcasting channel, and at operation 2401, may search for and checkwhether a cell exists through searching for the ITS frequency band. If acell that satisfies a specific condition is searched for in the ITSfrequency band (in this case, cell search based on the signal strength,such as S-measure, may be used), the terminal 2430, at operation 2402,may read the broadcasting channel of the corresponding cell, and mayreceive Tx/Rx pool information and threshold value information for CBRreport of the corresponding pool. In this case, the information may betransmitted through the broadcasting channel. The broadcasting channelmay include an ID of the corresponding cell. The terminal 2430 that hasreceived the information, at operation 2403, may use the Tx pool, andmay measure the CBR for the Tx pool. At operation 2404, if the CBRreport condition is satisfied, the terminal may determine to report theresource CBR for the Tx pool. At operation 2405, the terminal 2430transmit the resource CBR information to the serving BS 2410 that doesnot support the ITS band. In this case, the reported resource CBRinformation may include a measured CBR value and corresponding resourcepool information, ITS serving cell ID, and ITS serving cell band(carrier frequency band) information.

If the CBR report for the ITS band if the terminal 2430 is received, theserving BS 2410, at operation 2406, transfers the CBR information andthe resource pool information measured by the terminal to a neighbor BS2420 that support the corresponding ITS band. The terminal resource CBRreport and resource pool information between the serving BS 2410 and theITS band BS 2420 may be transferred using an X2 interface.

At operation 2407, the ITS band BS 2420 may change the resource poolthat is given to the corresponding terminal based on the CBR relatedinformation transmitted from not only the terminal 2430 but also otherterminals, or may increase or decrease the resource structure of thewhole pool.

At operation 2408, the ITS band BS 2420 may transfer the changedresource pool information through the broadcasting channel. In thiscase, the transferred information is not information only for a specificterminal, but is information for the whole cell, and thus the changedstructure information of a specific resource pool may be transferred.For example, if the resource amount of the past Tx pool is small, it maybe changed to a resource pool having a larger structure. At operation2409, the terminal 2430 receives the information, and may performcommunication through changing its own resource pool.

FIG. 2S is a diagram illustrating a process in which a terminal operatesbased on a predefined resource pool on the assumption that the terminalis out of coverage of a V2X service cell according to an embodiment ofthe present disclosure.

Referring to FIG. 2S, if a cell of the ITS frequency band is not foundthrough a cell search, or it is not indicated that the serving cell canperform cross-carrier resource allocation, the terminal assumes that theterminal itself is out of coverage of the V2X service cell, and mayoperate based on a predefined resource pool. At operation 2501,respective terminals (e.g., 2510) may measure the CBR for a resourcepool, and at operation 2502, they may transfer the measured CBR valuethrough a PC5 packet. If a plurality of pre-configured Tx pools areprovided, and the terminal can select a Tx pool among the plurality ofpools, terminals (e.g., 2520) that are out of coverage may receive theCBR value and pool information that are measured by other surroundingterminals (e.g., 2510) to be transmitted through the PC5 packet. Atoperation 2503, if reports, in which resource CBR value is larger than aspecific threshold value, are received over a specific level, theterminals (e.g., 2520) that are out of coverage may perform operationsfor optionally changing their Tx pools to other pools (e.g., resourcepools having the minimum CBR value).

Hereinafter, another example of the operation of UE that performsresource CBR report based on an event (e.g., event in which if theresource CBR is higher than the threshold value X, if the resource CBRis equal to or higher than threshold value A, or if the resource CBR islower than threshold value B, UE transmits the resource CBR report to aBS).

In the case where the terminal reports the event-based resource CBR, theterminal may transmit the resource CBR report to the BS immediately whenthe event occurrence is determined. As another example, if it isdetermined that the event has occurred and is effective for apredetermined time, the terminal may transmit the resource CBR report tothe BS. Configuration parameters (e.g., a waiting time per resourcepool, a waiting time per service priority, a waiting time per packetpriority, and a waiting time per logical channel group) used todetermine the event effectiveness may be indicated from the BS.Hereinafter, the operation of a terminal that operates a waiting timeper resource pool will be described. According to various embodiments ofthe present disclosure, the waiting time may be set by a resource CBRreport limit timer.

FIG. 2T is a diagram illustrating an example of a terminal operation foroperating a CBR report waiting time in the case of reporting a CBRreport per resource pool according to an embodiment of the presentdisclosure.

Referring to FIG. 2T, at operation 2601, the terminal may receive poolconfiguration information from the BS. The pool configurationinformation may include resource information of each pool, pool CBRthreshold value information, and pool resource CBR report limit timer.One pool resource CBR report limit timer may operate per terminal, ordifferent timers may operate per pool. At operation 2602, the terminalmay determine whether new pool configuration information is receivedfrom the BS. If the new pool configuration information is received fromthe BS, the terminal, at operation 2603, may adjust its own poolinformation in accordance with the new pool configuration information.If the resource CBR report limit timer operates, the terminal, atoperation 2604, may reset the resource CBR report limit timer value.Here, the reset of the resource CBR report limit timer value correspondsto setting of an initial value of the resource CBR report limit timer.For example, the resource CBR report limit timer may be executed afterthe resource CBR report is first performed once. For example, theinitial value of the resource CBR report limit timer may be set to 0 ms.At operation 2605, the terminal may monitor the resource pool configuredto be used by the terminal itself. If new pool configuration informationis not received at operation 2602, the terminal, at operation 2605, maymonitor the resource pool based on the received pool configurationinformation. At operation 2606, the terminal may check whether theresource CBR report limit timer is under operation. If the resource CBRreport limit timer is not being executed, the terminal, at operation2607, measures the resource CBR for the configured pool, and maydetermine whether the measured resource CBR is equal to or higher thanthreshold value A. If the resource CBR is equal to or higher than thethreshold value A, the terminal, at operation 2608, may transmit a CBRsituation report for the pool to the BS. Further, at operation 2609, theterminal may execute the resource CBR report limit timer. If it isassumed that the resource CBR report limit timer value for the pool is 1sec, the terminal may acquire an opportunity to transmit the resourceCBR report for the pool after waiting for 1 sec. The terminal mayproceed to operation 2601 to receive the pool configuration from the BS.

If the resource CBR for the pool is not higher than the threshold valueA, the terminal proceeds to operation 2611 to determine whether theresource CBR for the pool is equal to or lower than the threshold valueB. If the resource CBR for the pool is equal to or lower than thethreshold value B, the terminal proceeds to operation 2608 to transmitthe CBR situation report for the pool to the BS. According to anembodiment of the drawings, the threshold value A may be a thresholdvalue whereby it is determined that the resource pool is busy, and thethreshold value B may be a threshold value whereby it is determined thatthe resource pool is not busy. If it is determined that the resource CBRfor the pool is not lower than the threshold value B, the terminal mayproceed to operation 2601.

On the other hand, if it is determined that the terminal executes theresource CBR report limit timer by the determination of operation 2606,the terminal, at operation 2610, may determine whether the resource CBRreport limit timer has expired. The resource CBR report limit timer maybe used to limit the resource CBR report for the resource pool beingused by the terminal, and may have the effect of reducing systemoverhead due to signaling. Further, since the terminal reduces signalingfor transmitting the CBR report for the resource pool being used by theterminal, battery power consumption of the terminal can be reduced. Theresource CBR report limit timer may be reset in the case where theresource pool configuration of the terminal is changed. That is,overhead can be reduced in transmitting the same CBR report for the sameresource pool, and thus the CBR report can be transmitted for the newresource pool.

If the resource CBR report limit timer has expired, the terminal mayproceed to operation 2607. If the resource CBR report limit timer hasnot expired, the terminal may proceed to operation 2601.

FIG. 2U is a diagram illustrating another example of a terminaloperation for operating a CBR report waiting time in the case ofreporting a CBR report per resource pool according to an embodiment ofthe present disclosure.

Referring to FIG. 2U, at operation 2701, the terminal may receive poolconfiguration information from the BS. The pool configurationinformation may include resource information of each pool, pool CBRthreshold value information, and pool resource CBR report limit timer.One pool resource CBR report limit timer may operate per terminal, ordifferent timers may operate per pool. At operation 2702, the terminalmay determine whether new pool configuration information is receivedfrom the BS. If the new pool configuration information is received fromthe BS, the terminal, at operation 2703, may adjust its own poolinformation in accordance with the new pool configuration information.At operation 2704, the terminal may monitor the resource pool configuredto be used by the terminal itself. If new pool configuration informationis not received, the terminal, at operation 2704, may monitor theresource pool based on the pre-received pool configuration information.

At operation 2705, the terminal may check whether the resource CBRreport limit timer is being executed. If the resource CBR report limittimer is not being executed, the terminal, at operation 2706, measuresthe resource CBR for the configured pool, and may determine whether themeasured resource CBR is equal to or higher than threshold value A. Ifthe resource CBR is equal to or higher than the threshold value A, theterminal, at operation 2707, may transmit a CBR situation report for thepool to the BS. Further, at operation 2708, the terminal may execute theresource CBR report limit timer. Thereafter, the terminal may proceed tooperation 2701 to receive the pool configuration from the BS.

If the resource CBR for the pool is not higher than the threshold valueA, the terminal proceeds to operation 2710 to determine whether theresource CBR for the pool is equal to or lower than the threshold valueB. If the resource CBR for the pool is equal to or lower than thethreshold value B, the terminal proceeds to operation 2707 to transmitthe CBR situation report for the pool to the BS. According to anembodiment of the drawings, the threshold value A may be a thresholdvalue whereby it is determined that the resource pool is busy, and thethreshold value B may be a threshold value whereby it is determined thatthe resource pool is not busy. If it is determined that the resource CBRfor the pool is not lower than the threshold value B, the terminal mayproceed to operation 2701.

On the other hand, if it is determined that the terminal executes theresource CBR report limit timer by the determination of operation 2705,the terminal, at operation 2709, may determine whether the resource CBRreport limit timer has expired. The resource CBR report limit timer maybe used to limit the resource CBR report for the resource pool beingused by the terminal, and may have the effect of reducing systemoverhead due to signaling. Further, since the terminal reduces signalingfor transmitting the CBR report for the resource pool being used by theterminal, battery power consumption of the terminal can be reduced. Theresource CBR report limit timer may be reset in the case where theresource pool configuration of the terminal is changed. That is,overhead can be reduced in transmitting the same CBR report for the sameresource pool, and thus the CBR report can be transmitted for the newresource pool.

If the resource CBR report limit timer has expired, the terminal mayproceed to operation 2706. If the resource CBR report limit timer hasnot expired, the terminal may proceed to operation 2701.

FIG. 2V is a diagram illustrating still another example of a terminaloperation for operating a CBR report waiting time in the case ofreporting a CBR report per resource pool according to an embodiment ofthe present disclosure.

Referring to FIG. 2V, at operation 2801, the terminal may receive poolconfiguration information from the BS. The pool configurationinformation may include resource information of each pool, pool CBRthreshold value information, and pool resource CBR report limit timer.One pool resource CBR report limit timer may operate per terminal, ordifferent timers may operate per pool. At operation 2802, the terminalmay determine whether new pool configuration information is receivedfrom the BS. If the new pool configuration information is received fromthe BS, the terminal, at operation 2803, may adjust its own poolinformation in accordance with the new pool configuration information.The terminal that has received new pool configuration information mayset the resource CBR report limit timer value to “0” if the resource CBRreport limit timer value is not “0”. At operation 2804, the terminal maymonitor the resource pool configured to be used by the terminal itself.If new pool configuration information is not received, the terminal, atoperation 2804, may monitor the resource pool based on the pre-receivedpool configuration information.

At operation 2805, the terminal may check whether the resource CBRreport limit timer has expired. If the resource CBR report limit timerhas not expired, the terminal, at operation 2806, measures the resourceCBR for the configured pool, and may determine whether the measuredresource CBR is equal to or higher than threshold value A. If theresource CBR is equal to or higher than the threshold value A, theterminal, at operation 2807, may transmit a CBR situation report for thepool to the BS. Further, at operation 2808, the terminal may startexecution of the resource CBR report limit timer. For example, theresource CBR report limit timer value may be set to 1 sec. Thereafter,the terminal may proceed to operation 2801 to receive the poolconfiguration from the BS.

If the resource CBR for the pool is not higher than the threshold valueA, the terminal proceeds to operation 2809 to determine whether theresource CBR for the pool is equal to or lower than the threshold valueB. If the resource CBR for the pool is equal to or lower than thethreshold value B, the terminal proceeds to operation 2807 to transmitthe CBR situation report for the pool to the BS. According to anembodiment of the drawings, the threshold value A may be a thresholdvalue whereby it is determined that the resource pool is busy, and thethreshold value B may be a threshold value whereby it is determined thatthe resource pool is not busy. If it is determined that the resource CBRfor the pool is not lower than the threshold value B, the terminal mayproceed to operation 2801.

On the other hand, if it is determined that the resource CBR reportlimit timer has not expired by the determination of operation 2805, theterminal may proceed to operation 2801. The resource CBR report limittimer may be used to limit the resource CBR report for the resource poolbeing used by the terminal, and may have the effect of reducing systemoverhead due to signaling. Further, since the terminal reduces signalingfor transmitting the CBR report for the resource pool being used by theterminal, battery power consumption of the terminal can be reduced. Theresource CBR report limit timer may be reset in the case where theresource pool configuration of the terminal is changed. That is,overhead can be reduced in transmitting the same CBR report for the sameresource pool, and thus the CBR report can be transmitted for the newresource pool.

As described above, although the operation of the terminal that operatesa waiting time per resource pool has been described, the terminal mayalso be applied even in the case of operating a waiting time per packetpriority. Further, the operation of the terminal may also be applied inthe same manner even in the case of operating a waiting time per servicepriority or operating a waiting time per logical channel group.

That is, in the case of operating a waiting time per packet priority,service priority, or logical channel group, the resource CBR reportlimit timer may be set to operate with a value that is shorter than apacket having low priority so as to reduce delay time duringtransmission of a packet having high priority. That is, in the case of aterminal to transmit a packet having high priority, the resource CBRreport information is frequently transmitted, and thus the BS may bemade to secure a resource pool for a packet having high priority. In thecase of transmitting a packet having low priority, the resource CBRreport limit timer may be set to operate with a high value. In the caseof a terminal that intends to transmit a packet having low priority, theresource CBR report transmission frequency may be lowered to reduceresource CBR transmission signaling overhead due to the packet havinglow priority and terminal battery power consumption.

The resource CBR report limit timer may be applied in association withthe resource pool and the service priority, and different resource CBRreport limit timers may operate with respect to a pool having highservice priority and a pool having low service priority.

FIG. 2W is a block diagram schematically illustrating the internalstructure of a terminal (e.g., V2X UE) according to embodiments (e.g.,first and second embodiments) of the present disclosure.

Referring to FIG. 2W, a terminal may include a transceiver 2910 and acontroller 2920. The transceiver 2910 may transmit/receive data to/fromoutside (e.g., BS or another terminal). Here, the transceiver 2910 maytransmit/receive data to/from the outside under the control of thecontroller 2920. The transceiver 2910 may include at least one RF modulethat supports various kinds of communications.

The controller 2920 may control the state and operation of allconstituent elements constituting the terminal so as to performoperations according to embodiments of the present disclosure. Thecontroller 2920 may include at least one processor.

FIG. 2X is a block diagram schematically illustrating the internalstructure of a BS according to embodiments (e.g., first and secondembodiments) of the present disclosure.

Referring to FIG. 2X, a BS may include a transceiver 3010 and acontroller 3020. The transceiver 3010 may transmit/receive data to/fromoutside (e.g., terminal or another BS). Here, the transceiver 3010 maytransmit/receive data to/from the outside under the control of thecontroller 3020.

The controller 3020 may control the state and operation of allconstituent elements constituting the BS so as to perform operationsaccording to embodiments of the present disclosure. The controller 3020may include at least one processor.

While the present disclosure has been shown and described with referenceto various embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present disclosure asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method for supporting a vehicle to everything(V2X) service by a terminal, the method comprising: receiving thresholdinformation for reporting a channel busy ratio (CBR), the thresholdinformation including a first threshold and a second threshold;identifying a zone where the terminal is located in based on a locationof the terminal and zone-related information; identifying a resourcepool corresponding to the zone based on resource pool information;measuring the CBR for the resource pool corresponding to the zone;reporting the measured CBR if the measured CBR is above the firstthreshold; and reporting the measured CBR if the measured CBR is belowthe second threshold.
 2. The method of claim 1, further comprising atleast one of: identifying whether the measured CBR is above the firstthreshold; or identifying whether the measured CBR is below the secondthreshold.
 3. The method of claim 1, further comprising: receiving atleast one of the zone-related information, the resource poolinformation, or threshold information for measuring the CBR, wherein theCBR for the resource pool corresponding to the zone is measured based onthe threshold information for measuring the CBR.
 4. The method of claim3, wherein at least one of the zone-related information, the resourcepool information or the threshold information for measuring the CBR istransmitted by being included in at least one of a system informationblock (SIB) message, a radio resource control (RRC) connectionreconfiguration message or a pre-configuration message.
 5. The method ofclaim 1, further comprising: receiving transmission power informationfor transmitting data.
 6. A terminal for supporting a vehicle toeverything (V2X) service, the terminal comprising: a transceiverconfigured to transmit and receive signals; and at least one processorcoupled with the transceiver, wherein the at least one processor isconfigured to: control the transceiver to receive threshold informationfor reporting a channel busy ratio (CBR), the threshold informationincluding a first threshold and a second threshold, identify a zonewhere the terminal is located in based on a location of the terminal andzone-related information, identify a resource pool corresponding to thezone based on resource pool information, measure the CBR for theresource pool corresponding to the zone, control the transceiver toreport the measured CBR if the measured CBR is above the firstthreshold, and control the transceiver to report the measured CBR if themeasured CBR is below the second threshold.
 7. The terminal of claim 6,wherein the at least one processor is further configured to perform atleast one of: identifying whether the measured CBR is above the firstthreshold, or identifying whether the measured CBR is below the secondthreshold.
 8. The terminal of claim 6, wherein the at least oneprocessor is further configured to: control the transceiver to receiveat least one of the zone-related information, the resource poolinformation, or threshold information for measuring the CBR.
 9. Theterminal of claim 8, wherein the CBR for the resource pool correspondingto the zone is measured based on the threshold information for measuringthe CBR.
 10. The terminal of claim 8, wherein at least one of thezone-related information, the resource pool information or the thresholdinformation for measuring the CBR is transmitted by being included in atleast one of a system information block (SIB) message, a radio resourcecontrol (RRC) connection reconfiguration message or a pre-configurationmessage.
 11. The terminal of claim 6, wherein the at least one processoris further configured to control the transceiver to receive transmissionpower information for transmitting data.